We have four kids under seven. Don't your kids ever sleep? Ours do, thank goodness. Install a lock on the bedroom door, make sure no one can see UNDER it or through a keyhole, etc (you'd have to worry about that only in a very old house, or course) and get a small stereo for cover noise. Get creative! Set that alarm and get up an hour early. you'll be in a great mood all day.

Also, a bunch of little kids make for a lot of work. Make sure you are doing your share, so your partner is not too tired to find time in the sack.

(I apologize for declining to answer some of your questions, but I think this should cover what you're really asking. How often anyone does it is a personal preference issue. But my point is that you can certainly do it every day if you both work towards that as a goal. I urge you to consider housework as foreplay, it's an amazing tool to get a lot of mothers in the mood for other things!!!!)

if you already have three children under 7 perhaps you should abstain for awhile - you certaintly wouldnt want four children under 7 ;-)

i agree that making sure you help your spouse with all of the house and kid chores will certainly make her feel more bonded to you in a "we are in this together" and thus she will more comfortable and less stressed and the time will be found when the moment is right.

treat her to a spa day - facial, massage, pedicure and manicure while you watch the kids ... when she gets home she will feel sexier and need to show off her newly spa refreshened skin.