NC, This is my first time signing on to DB for quite some time. I have lurked from time to time but when I saw your post about leaving DB I signed on -- had a hard time remembering my password!
I know living with such strife day after day after day is anguishing. I think Karen had a good point about your ex's. It makes an already impossible situation even worse.
I wish I had some words of wisdom for you but can't find any magical answers. Children need and want consistency in their life. Unresolved anger and frustration creates a significant barrier to co-parenting, that's for sure.
If she is going to marry OM, it is entirely in your right to request to meet him if he is going to have any kind of role in parenting your sons. If you can't communicate at all with your ex, perhaps it will be possible through him. (May not sound like an exciting plan but think of it as a 'back door' tactic.)
I hope you stick around. If I get the courage, I may come back. I'm about ready to throw in the towel in my M....