Why are people that are secretly gay, stay in opposite relationships?

I would like to know the answer to that question also. I too have been a witness of this and don't seem to get it sometimes. I do hear that most gay men wanted to raise a family and that's one of the reason's why they choose to be married to a woman. I can understand that part somewhat but if you feel that you like both es and you can't commit to staying faithful with your spouse, then you shouldn't get married. That's how i see it.