Welcome Nitty, Yes, I got the old "I did TRY" from my W as well. If she did, I sure as heck never saw it! To them (MLCers) trying isn't the same as the rest of the universe. At one point (not long after B-day) my W said she would do some anti D program. It had a workbook and one week you were supposed to do this, next week you were supposed to do that. The thing is she never did any of it! After the first week she got angry and told everyone I was trying to "guilt" her. I never once tried to guilt her, if she felt guilt it was because of what she was doing, not because of anything I had done.
Does your H really think that dating other people while M is "OK" and not any worse than getting a D? Look at the crazy things he is saying and doing and know that he is the insane one, not you. I know there were times that I bought into her "You're the reason for this" chit. Do yourself a favor and don't do that if you are able. Be careful. My W has now filed and has reneged on EVERYTHING she had agreed to (and I let her have things that I never would have if I had known she would be doing this). kml is right, get a L. I offered to do mediation and my W agreed but changed her mind and hired a L and then told me that I didn't need one! This person who didn't have a sneaky bone in her body for 26 years, now has been screwing me behind my back all this time.
He may think dating while M is OK but you do not! You are in the right to tell him that that is just not acceptable and the D is HIS doing, not yours in any way. Protect yourself, be glad the kids are old enough that it doesn't affect them too much (although it does and they will be hurting as well). It stinks that you must be where you are but you can and will get through this. Be strong and post whenever you need! We are here for you!