Should I stay with my fiance or boyfriend?

I met my fiance while in Iraq. He is from England, I am an American woman. He was kind of a geek, but I fell in love with his heart or this person I thought him to be. I came home for over a year I was faithful to him, while he lied and took R & R's to see another woman, (who rudely rejected him). He kept lying and was rude at times. I took our love serious and he didn't. About a month ago I met a wonderful man, and things are really blossoming. He treats me like gold. My fiance is finished in Iraq & partying hard in England and wants to come home in a week. He said he is sorry and loves me with all his heart and wants only me. I still love him, so it hurts to hear these things, but I don't believe him. My boyfriend is a Christian, my fiance is an Athesist. My boyfriend is responsible and ambitions, my fiance is lazy. But I am not a robot and can not change my emotions & I still love my fiance? Please help