Difference in sex drive

My fiancé and I have completely different sex drives. I would have sex with him every day but I'm lucky if he has sex with me once a month. We have been together for four years and we had a great sex life at first but it has slowly trickled down to nothing. Mind you we are 22 and 25 who live together without kids. Anyone have any suggestions? I have tried gentle suggestions and massage and snuggling. It never leads anywhere. Help!