Lots a good advice here, so not much to add, only to reinforce thr primary points:
Yes, my take is that the wife is quite selfish & manipulative...& the girls have learned well from mom what gets results...
I don't think willingness to go into therapy is a mixed signal, you DO have your son to think about...& I'd say he needs you to be there for him, to give him an escape hatch from that squirrel cage...

__________________
Plug me into somethin'

If the theory does not conform to the facts, then the facts must be discarded.

No good deed ever goes unpunished

Never argue with an idiot. He'll drag you down to his level, & beat you with experience.

I would imagine that being on the other side of the situation (i.e., having your spouse ask you for divorce because they don't love you anymore) would be unbelievably difficult to accept and get over. Especially on top of her problems with her daughters. I understand that these things happen and that it is not anyone's fault, but it doesn't make it any easier to deal with. I think thats great that you are trying to help her deal with the issues at hand, but I agree with Lou about the possible mixed messages. Perhaps she should be the one going to therapy alone to help her get through these things. If you have made up your mind to finalize the divorce, then I see you going with her to "couples therapy" as maybe giving her a false sense that maybe you will change your mind. I think that the only way you can help is to be there as a supporting friend. Going on dates and accompaning her to counseling would break the boundaries that you are trying to make with getting a divorce. Hope this helps.

1nutworld, you are so selfish.

You should be willing to destroy your life and sanity and damage that of your child

to satisfy some murky agenda of your (soon to be ex) wife.

Shame on you.

Sorry? My medication again so soon? Be right back.

__________________
Calm, quiet, smooth, devastating

Thanks for that OF....I Truly deserved it.

Thanks, too, to everyone for their advice, and obvious support.

I don't like what is happening to me, and am still angry, and to a lesser degree bitter, but I know I have to accept things and move on. My goal is now just try to learn from these lessons. I'll still be involved with my son and his life, and we will have to do the best we can when we are together.