There is no serious problem here. I bet the fact that he is no longer sexually interested in you doesn't mean you are a woman who is not sexually attractive to other men at all. As matter of fact you said "现在仍有几个以前的男同学喜欢我". But be aware of this: once you go to bed with those 以前的男同学, then the 喜欢 can't last too long either.
On the other hand, marriage and family have other factors to hold it together. A man's fantasy of being with different women shouldn't danger your marriage per se.
Best wishes in the new year.