No sex drive at 30 yo???!

I have no sex drive. I could probably go months without sex. It is never on my brain. I very rarely have the urge to have sex. And it is affecting my relationship! I do believe that part of the issue has to do with two things: one, I have weight issues and two, my fiance cheated on me and I cant get him with another woman out of my head. I want to be attracted to my husband but somethings go to give....