The ability to compromise is very important indeed. If you can agree to each give a little, things work out so much better in the long run.
However, as I'm discovering w/my X, you do need to stand your ground and make sure that X is not trying to dictate terms or be controlling of the kids. You have every right to tell her that if an agreement isn't made w/you two, she can't just decide on her own that she's going to do something.
She is accountable to the agreement of the divorce and you are completely w/in your rights to let her know there are legal consequences to her actions if she doesn't want to try and involve you in the process.
I've done the same w/my X and it is amazing how quickly she comes to the negotiating table when I let her know that she's not legally allowed to do whatever she wants w/our D.
