You did not say which one of you is a U.S. citizen. Considering that your fiance is still here after all his convictions, it seems a safe bet that he is an American. If so, his convictions do not matter: they do not disqualify him as a petitioner for his wife. If, however, you are a U.S. citizen, and your fiance is an alien who was not deported after serving his sentence, the situation is different. After you marry him, you can petition for his visa, but it will serve no purpose because his criminal record makes him inadmissible to the U.S. (which means that he cannot enter the country on any visa and cannot become a permanent resident here).
Answered on Oct 24th, 2012 at 2:11 PM