Allowing SS16 to Make Decisions re: Visitation with BM
I'm hoping I can get some advice on a decision DH and I made recently with respect to SS16 visitation with his BM, who lives about 4 hours from us. He currently lives full time with us, and visits with BM every 2nd Christmas, every 2nd March break, 2 weeks during summer, and occasional long weekends during fall/winter. These dates were agreed upon in an informal written agreement between DH and BM. And, I want to add that BM was okay with this arrangement and wasn't interested in spending more time than was stated in the agreement.
So, fast forward to last month when SS turned 16. We decided that from now on SS would make the decision of when he wants to spend time with BM. If he wants to spend every Christmas or March break or all summer with her, we're okay with it. If he doesn't want to go there at all, we're okay with it. We're pretty certain that BM will discourage more visitation than she has currently, but we've gotten to the point where we don't want to deal with it anymore and we don't want to be the ones who (in SS's eyes) are in full control of the whole thing.
My question is this. What are the likely pitfalls of us stepping back and leaving these decision to SS and BM? Are we setting ourselves up for manipulation by BM?
Any advice would be greatly appreciated.