In my situation, I am the Dad, Mom was ordered to get an extra bedroom for our daughter. There was no abuse going on, but they felt my daughter should have her own room. Keep in mind I didn't ask for that, but it was still ordered. I dont see anything wrong with a little girl sleeping in the same bed as a Daddy, conversly I also see nothing wrong with a little boy sleeping with his Mom.
The funny part of this was that Mom was unemployed and living with her parents. She had to ask her parents to move so that she didn't loose her daughter. Grandparents weren't thilled with having thier lives turned upseide down, but they'd do anything to keep my daughter with them away from me.
I didn't see anything wrong, so to say, with them sharing a bedroom, but it is better for my daughter now.
So, in my opinion as long as you are sure there is no abuse going on don't go to court. Just ask your X to get a cot for him to sleep on while she is there. Tell him she is just getting too old for that and needs more space. Tell him it will help her develop emotionally.