Well last night everything came to a head.
I told him he had to stop seeing W, because I couldn't handle that it started with an affair. If this is the life he wants, that's fine, but I needed a clean slate. He said ok, and said he wanted to talk to her and explain things...
No. Absolutely not. I know it probably makes me a terrible person, and I'll catch hell from people here for saying it, but there was no way I was going to allow it. The look on his face and the tone of his voice almost made me snap. In that moment it felt like he was more concerned with hurting her feelings than mine. It was like finding out that he cheated all over again, and it broke my heart.
I sent her a text telling her it was over, and she responded by saying when it started she didn't know he wasn't single, which is BS (I read their messages on LL, she knew). Now he's mad. He wanted to let her down gently because she has low self-esteem etc. Funny, he didn't care to let me down gently when cheating (twice), even though I'd just had his baby and was diagnosed with PPD, and my body image and self-esteem were at an all-time low.
I don't know what's going to happen now. We've talked about therapy but he doesn't seem terribly interested...
In short I just wanted to thank everyone for taking the time to read and comment. I know I've been on a bit of a rant about the whole thing, but this isn't something I'd be able talk to my friends or family about. Thank you!