Please help, I'm miserable!

So My boyfriend is not as sexually active as I am. He comes very quickly every time we have sex. ( We've been together for 2 years, also we weren't virgins before either.) Also sometimes He goes soft before he even enters me.. I asked him if he's not attracted to me and he says that's not it. But never ever has he made me orgasm. ( No guy has for that matter.) but it just sucks. I'm never satisfied, and we don't have sex that often either. Maybe once or twice a week at most. I'm at a loss as for what to do... I love him very much, and we are getting married soon.. Is there something besides viagra that could help? Does anyone know of anything?