Orgasms

Guys Im starting to get really worried. I used to masterbate and climax every night before bed. when I get into relationship my sex drive dives down. I don't know why and it's really frustrating. My fiance moved in about 6 months ago and I've only climaxed once since he moved in and I have no sex drive whatsoever. I was in the mood the other night and no matter what I could not finish. It was really frusterating because I got so close and couldn't jump over the ledge. I acrually starting crying and got depressed and I just dont know what to do because I dont even want to pleasure him anymore because it makes me feel gross and just sad.... is there anything I can try?