Well, it's a start. He now needs to follow that up with actions, words, etc.. It is a two way street of course so don't be hostile with him. Accept him with loving boundaries.
1)There can be no contact with OW, period. No email, no TM, no FB, MS...nothing. 2)She is to be blocked from all contact points and removed from all lists. 3)If any of these boundaries are violated, he is to immediately leave the house until he is actually ready to get out from under her hold on him.
Something of that nature. Any contact with OW in any way (oh, we're just friends now..blah blah blah..) is unacceptable and detrimental to your M.
Sounds harsh, I know. Of course, what he's been doing to you is harsh too....
Absolutely agree with Mishka here, Ashley. Now is the time (when he's claiming to want to work on the M) to do this.