Sex trouble

Okay, I have been dating this guy for a year and 3 months and lately I just haven't been sexually satisfied.. I have NEVER had an orgasm unless I do it myself.. when we do have sex he always finishes and when he does he's basically done, and then wants to snuggle. I get so moody and mad about it and I don't know what to do.. lately I've been watching a lot of lesbian porn, and that seems to be the only way I get turned on and I'm starting to think I want to do things with a girl... I am not gay or anything, I guess I know a girl wouldn't just finish and leave me there hanginging... idk what to do. For the past month and a half I have with held sex and I don't even have an urge to have sex.. because I know if we do I won't have an orgasm and it won't be fun for me. What should I do? I know this is terrible but it's causing me to lose feelings for him emotionally as well, because I feel as if he is being highly selfish.. I love him very much  and I don't want to break up, but he knows I'm not enjoying it... and I know sex issues lead to break ups. Can anyone help?