How do you know when a married man fancies you?

If he or she flirts with you but be careful you can't always tell if a man or woman is married because most of the time married men and woman don't wear their wedding bands. It's better to keep to yourself in this day and age. The alternative would be to ask a lot of questions and have him show you the answers, EVIDENCE don't take his Word for it. Don't take her Word for it.