Really ponder what Ellie said, logic often gets tossed aside.
Mediation Before court, Legally binding mediation is an option in many states.
Edit: (Posted after you, just read yours. There is such a thing as BINDING mediation, did you explore that option? What the mediator comes up with both have to abide to. Sounds like the mediation you went to was a guideline(?) which helps but still left you without an agreement and a problem.
Your Brother You mentioned he is nice but a "bull" if you cross him. Could you have your brother negotiate for you? Tell X this is a business transaction and all you need to do is make decisions, the kids do not need to see EITHER (him too) of their parents under additional stress.
A personal example To what Ellie said, I hated being distanced from my kids, having them not live under the same roof with me. It is more horrible than most female DBers realize or ponder (yes he left but the pain is still there which supports Ellie's point)
After the D, X and I were having challenges communicating, usually about the kids. Mostly email, some conversations but things would get heated a couple of times a month. Her new husband suggested to her that he and I work out differences in the future and I resisted, didn't trust him. We met face to face over a different issue and he made the suggestion again but this time I agreed that if an issue was getting heated, that he and I would work it out. (He also said he would continue to encourage her to stay out of my business).
He knew she got emotionally involved and that he and I could deal with things in a more business like manner.
My story supports Ellie's point that we dads want to hang on to that contact for different reasons but that because of emotions from both spouses, sometimes having an in between person for certain issues (your brother, my X's new husband) may make sense.
Committed2Him- "C2H" All Things (Back from Spain!)...18