Whats wrong with me :(

I've been with my partner for 4 years and we have a baby together and i have 2 children to a previous marriage. Up until recently (past year) our sex life has been great but something happened and it went to . First I thought maybe he was tired cause of work but there has been many instances where he has not had work (weekends, holidays etc)
I can only reach orgasm by rubbing my clit or occasionally oral, which my partner knows.

I always make sure he is satisfied, he always cums even if i cant actually have ex (that time of the month, or in this case i had our baby 2 weeks ago so haven't been able to participate in sex). I give him blow jobs or hand jobs. When we do have sex or begin to start fooling around he makes no real moves toward's actually turning me on...(goes in dry more then half the time) And after he finishes unless he is wants to go a second round I'm out of luck. This is if he doesn't fall asleep during me wanking him off or sucking him off, sometimes we are lucky enough that he remains awake..
When he does bother to touch me he goes straight for my clit like a bull at a gate and if anything it hurts. He doesn't try to touch me in any other way.

I just don't know what to do. I cant help but think what is wrong with me, if i want to come i have to watch porn and deal with myself privately (which is what i do most days anyway) but to have to do it when we were meant to have just had sex or whatnot is horrible It's at the point that after sex I end up leaving the bed while he goes to sleep to go cry in the lounge room.

I know he loves me he tells me all the time. He always kisses me, holds my hand, kisses my forehead...But the sex is just awful or non existent.

I try everything I can to make sex good for him. Just about anything he asks me to do for him I willing do it happily. But every time I ask anything of him, he says he will but doesn't or does it one time then never again.

I don't think i turn him on anymore, maybe cause i have put on weight thanks to the pregnancy....or maybe I am not attractive because of the changes my body went through during pregnancy and after.

While I was pregnant and a bit before i found messages in his email. We were having a few communication issues and because of this he started messaging other girls telling them he was single. He was answering to adds on craigslist as well. I don't know what to do, I'm terribly depressed because of our sex life because i love him so much but maybe I'm a fool