Not sexually attracted to my fiancé! HELP!

For about a month or two now, I haven't been sexually attracted to my fiancé. We haven't had sex in about a week or two. And I just don't enjoy it. He only lasts like 3 minutes. NO JOKE! It's not because of that, I just don't know. I just don't wanna have sex with HIM. I'm constantly wanting sex, but not with him. PLEASE don't judge me, but sometimes I wanna just have sex with other men. I WONT, but that just how I feel. Is something wrong with me?