I know what you are going through - I have been there in the past and it still is the case every once in a while. My BF wants to guilt parent because he only has his daughter EOWE, and gives in to her and lets her get away with things that the other kids can't. He says because "she is only here EOWE, and I want her to have a good time."
I was suggested once - maybe on this forum that it is better to apologize than ask for permission. I took it into my own hands to discipline SD6 how I felt fit when she is here and BF is at work or out of the home for whatever reason. I also told BF that I wanted to parent SD6 as if she were my own and not have to ask for permission for punishing or scolding, after all, if she is in my care it is up to me when he is not around.
Be careful - if your SDs get the impression that what you say does not matter because dad says otherwise, eventually they will stop respecting you. This is what happen to me...SD6 started rolling her eyes at me and instigating my son to get him into trouble when her dad was not around. As soon as I told BF I was gong to parent her as if she were my own, thing improved 10 fold and I don't feel like I have to ask for permission - I just do it.
That's the best I can do for you, I hope it was helpful.

When I was reading what you wrote, I stopped and I said my situation reminds me of mine in a way(concerning my husband)When you said your husbands response is always she is only 3...she's only 4...she's only 5.My heart dropped for you because that's what I have been told since my stepson has been 2 now he is 9. The same excuse always till this day! I guess am not the only one. I just want to say I think you are doing a great job. This is a tough one because I know what you are going through. Some parents I think are in denial, about there children. Screw everyone else, everyone else is also not in your shoes. If your husband is working OT that is not your job to be watching both of them, that is your husbands job.If you end up watching them for him and they act like this and your husband doesn't want to hear it....then I would not get them when he is working. I know this is really hard, you could try to sit down and speak with him about this. Truthfully, I don't think this will get any better. Am not saying this to depress you or anything. I just want you to think of your life ahead of you. If you decided to have children of your own, it's going to be a lot harder. You are still young, I wish I had made different decisions in my life. I was like you and then I brought children into this mix, I regret not sitting down and saying if it's hard now, it's not going to get any easier. No one told be or gave me advice. I am giving you advice, I have been in your shoes. You don't have to go divorce your husband or anything....but in a way you are still free. When you bring a child in this situation you will have to deal with this forever!!! The best advice I could give you is just talk to your husband.Express how you feel. I wish you the best of luck.:)

The 'she's only 3 ... Only 4... Only 5...'thing is something I think bio parents tend to do. Especially in a divorced family. I sometimes say it and ExDH used to say it and it was very annoying to his wife. It gets annoying to my husband as well. Until we had our own baby and sometimes I get upset about something and my DH will say 'but he is only 3'. I think sometimes bio parents are more sensitive to their children and defensive especially when someone else is 'complaining' suggesting 'noticing' things about the kids... I think this is normal. Probably not a healthy form of parenting especially when they get to be 8,9, and up.

I'm sorry you are feeling the way you are and I hope you get it worked out with your Dh. I can only imagine how difficult it is and I as a parent/wife really try to be more sensitive to my husband when he is parenting our kids but honestly I feel the same overprotectiveness for both of my kids regardless of their paternity. And I think I have gotten my husband to understand that his overprotectiveness of our son is the same as mine of my daughter. He gets it now.
I also think stepparents, teachers, friends etc are not emotionally attached so they can stand back and see through clearer glasses than a parent who feels guilty over divorce through their foggy glasses. My dad is my stepdad and he loves us the same. He raised us and is by all accounts MY dad but he is more objective than my mom on many levels. He can say No clearly and mean it. He can stand strong and say 'I know you don't like this but it's the best for you in the end'. Like a doctor can 'inflict' pain on a child that is necessary where a mom or dad migh not be able to without cringing or stopping.. Like putting an arm back in place or stitching up a wound without medication because it's not available. Does that make sense? (granted this is not 100% the situation plenty of mom's and dad's hand out shots and medical treatments daily because they have to) I was just using an example.

It must be very hard for you. My DD is 23 and I cannot imagine her raising 8 and 6 years olds. I don't know what to suggest, sounds like you have way too much on your plate...

Thanks for all the advise. I have talked to my H since. I'm still not sure he knows exactly how I feel but I think there is at least a better understanding. I am so glad that there are people out there that are in similar situations and know how it feels.
"He says because "she is only here EOWE, and I want her to have a good time."
I get this all the time! And I understand that he doesn't want them leaving mad at us, but seriously we still have to be the parents
and also
".My heart dropped for you because that's what I have been told since my stepson has been 2 now he is 9. The same excuse always till this day! "
I'm so glad that this isn't just my husband, I know people are more sensitive about their bio kids but its frustrating when you can't teach them something because they are 'only..'
We sat down and made a list of rules that are going to happen in our house and what the consequences are if you don't follow. We also made up a list of chores. I'm hopeful. We will see what happens. I'll probably never get my H to fully understand how I feel, but now I feel there is at least an even playing ground as far as what is acceptable and what isn't.

My ex used to tell me "I don't want to be a bad guy because DD is with me only on the weekends". So because she is with me during the week i have to be a bad guy? So I was responsible for boring daily stuff and he entertained DD on the weekends. weird logic...

Its a catch 22 with divorces.

The weekend parent feels deprived of time with the child and does not want to be the bad guy and turns into the "Disney parent" where the whole weekend the child is spoiled and allowed to do whatever they want to keep them happy. The child then acts up a lot during that time because they know they can. But the parent feels so guilty that they don't see the child all the time that they just give into it.

The parent that has them during the week is stuck with the day to day hassles of homework, chores, bedtimes, etc. and does not get to play "good guy" all the time. So the child then tells this parent how much fun they always have with the other parent. And this parent gets the brunt of the child's poor behaviors and is forced to be the one to be the bad guy and deal with it.

Neither scenerio is any fun. I hope that your H sticks to his comprimises with you and it works out. Whatever you do, do not give in to this child's behaviors because it will only get worse as the child gets older. Its much easier to fix now.

"she is only here EOWE, and I want her to have a good time."

translation:
"she's only here EOWE, & I want her to like me."

which wouldn't be a problem if he weren't making you the scapegoat for her "unhappiness" as evidenced by fit-throwing (if she's throwing a hissy, she must not be having a good time).

& since throwing a hissy results in lots of grown-up attention & uproar...
then she *is* having a good time!

Sometimes the best thing to do is to disengage-

If you can't do anything right, don't do anything.

He may adjust his perspective after he's spent a few week-ends coping with things on his own.

I wish you the best.

What Sylvia said!

"He then proceeded to attack me with how I think his children are "demon spawn" and how everyone else thinks they are SO well behaved."

Was that a phrase you've EVER used? "Demon Spawn"? If not, then why would he refer to his own children using that term? It could be insight into HIS thoughts... just my thought on it.

--"The younger SD went into a screaming/crying fit. I asked them both to leave the barn because the older could have easily given her the broom and the younger didn't have to make such a fuss. "--

I'd likely be annoyed little sister is to get her own way and that I'm expected to give it to her so she won't cry/fuss/whine too. Personally I would have handed each child a broom and said 'here, this is the one you are using today'...since that was not first thing done, secondly I would not have the idea that 8 yr old should give in to 6 yr old just to shut her up.

In my opinion the only 4, 5, 6 only plays part in this when it comes to Dad giving these kids excuses. From what was posted it might be a bit of younger sister has learned how to manipulate you/Dad/sister into getting what she wants. And the attitude of 'older could have easily of given younger' may just be feeding the tirades of the younger child.

With younger child tossing hissies and getting her way, if I were her 2 yr older sister I'd likely think I just might try that method too. Hey, works for little sister. It could also be building strong resentment between the girls. I'd be mad if I had to give into somebody to shut them up. This six yr old does not get away with this at school you can bet on that. A soon as she would fit over someone having what she wanted, the teacher's attitude would not be 'oh ok, kid give the crying/whining little girl what she wants to shut her up'.

I think prehaps Dad and you need to sit these girls down and have a talk. What is occuring is unacceptable. Should not matter if it is you tending the kids for the day, just Dad or the two of you together. Dad is wrong to excuse behavior. Bad lesson to teach a kid. You are wrong in thinking oldest should cave to smallers hissies.

It is hard to only have the girls every other weekend but sharing, taking turns, listening to rules and following them should be expected ...it's not optional. Whether it is you or Dad, when you tell them they can not act this way around around animals they need to know exactly why. Not just are they not listening and being naughty, they are changing getting kicked, getting you kicked, hurting the horses blah blah. It's not going to matter if these girls 'are only 4, 5, 6' kicked is kicked. My DH is deaf in one ear due to being kicked on the side of the head by a horse (no he was not scaring them or mishandling them, he was flying with them and they got spooked by storm)

The age difference should not be a real big factor in that whether you are 23 or 38, when these girls are left in your care for the day, it's not so much (IMO) that you think they are demon spawns, but that they are indeed acting like little demons. You have to get the 'give the younger kid her own way' nipped and nipped immediately. If they both insist on acting like 2 year olds, you might have tried 'fine, you both can go sit on that straw bale and think about your behavior while I finish this'.

Alot is going to depend on how the girls are allowed to behavior the other 20something days a month. If they really are 'well behaved' except for when with you...you need to change your tactic in dealing with them. If they think they can run over you, they will. With you being closer to their age than their parents, they may have a tendency to not view you as an authority figure. If so, Dad needs to work on that too. Most 1st and 2nd grade teachers are young 20's these days. Children respect them and listen to them and are disciplined by them on a daily basis.