Please Help, I don't know what to do...

My SO has been watching porn since before we met, at this point he (watches, downloads, looks at) porn almost every other day. I work 40+ Hour weeks now since he lost his job a year ago. He is 32 and I'm 19, he has recently brought his ex back into his life (which he bent over backwards in their relationship to keep her happy including giving up porn) and she is pregnant with her current boyfriends baby, but keeps updating my SO with her baby progress like he is the dad which irritates me. Also she keeps asking how we are doing. He constantly turns me on and then says he isn't in the mood, especially on the days that he has watched porn. I have tried talking to him about all of this before and he only responds with "I'm old enough and been doing this longer since you have been around so I shouldn't have to change,) anything", "If you don't like it just leave", and "She's trying to be BOTH of our friends but your the problem here". At this point I don't know how I should feel or what to do because we have been TTC our first baby (especially since she suddenly appeared and bragged about being pregnant) and now I'm almost a week late for my period.