How do I make a married boy friend love me more than his wife?

If there is a man that is still married to a woman the chances are that he loves her a lot and is only lying about it to have you as a lover.

Assuming that he is not lying, then you have to do what his wife does not. It can be the intensity of your love, or the way you have sex, or the gifts that you give, or the things that you do for him.