Just not happy

So i'm at work today. Def feeling depressed and not sure how to cheer myself up. I don't even know how to write this without crying here. For those of you who don't know, I've cheated on my husband countless times and hurt him really bad but we have worked through it each time and stayed together. He knows i was abused as a child and it really messed me up so he's trying really hard to be there for me and help me through my issues. Well, the other night, he was at work, looking through some pics on his phone and apparently he had taken a pic with his phone of an email i had going with a guy before. Well, it pissed him off thinking back to those hard times and he was like, you know what? why the f can't i have my fun too? so now he's been going on craigslist looking for girls to hook up with, but he keeps coming home saying he's found his dream girl. That really hurts me. I do everything for him. The only issues we have is my cheating and we're working on that, or so I thought. I really think I'm losing him. If he finds a girl he's more compatible with than me, what am I gonna do? I really don't wanna go through a divorce and be a single mom to Aaron and have to ship him between two households. He deserves better than that. But I think i screwed that up when I cheated. And I feel I can't tell him he can't look and have his fun cause i had mine, you know? I just don't know what to do anymore. Let him try this and see if it's what he wants, and hopefully he doesn't leave me for another girl? or tell him no and risk him still hating me? These birth control pills i'm on have severly depressed me so I'm always sad and wanting to cry and I could really care less for sex, which is good, cause i don't wanna cheat anymore, but that means I also don't want it with him either. Its just not enjoyable to me. The pills depressed me which got me thinking about sex, and how it's ruined my relationship cause i chose to go outside my marriage for sex, thats it, nothing else. So now, to me, sex is a bad thing, just as it was when I was younger. It doesn't do any good. The only good thing that has come from sex has been my son. And that's what I'm living for right now. For him. I think he has kept me going. Well, I need to stop typing before i start crying and that's all i need here at work.