What Should a Citizen Do If His Fiancé Leaves Him For Another Man?

I am a U.S. citizen. I filed for my fiancé of two years to come to the U.S. so that we could marry. When I visited her overseas, I got along very well with her and her family members. When she arrived at Kennedy, I was there to meet her and everything seems fine. I left for work the next day, but when I returned home she was gone. I heard that she is staying with her old boyfriend. I still love her and want to get married. What should I do?
I am so sorry to hear of your situation. This happens sometimes. This does not ease the pain in your heart, but rest assured that under current law, your ex-fiancée will not be allowed to change her status to permanent resident on this trip. For example, if she should marry the love of her life, he will have to re-file for her, and she will have to return to her country to get her permanent resident visa.