8 years ago, Melania had a boyfriend named Hank Siemers, but I believe they broke up early in trump's first term. trump probably paid him to go away, but if he is willing to accept money to walk away from her, he must not have cared that much for her. He was head of security for Tiffany's(the store, not Melania's step-daughter).
No idea if he has been replaced. It appears that Melania will move to NYC, while trump will move to DC, with a side base at Mar-A-Lardo. They will continue to live separate lives.