I'm a guy who has the mentality to "never ever cheat on a women" if I'm already dating one, and its probably not only me. I think all guys are like that when they fall in love, but my question is, why do some guys still cheat on a their gfs or vice versa when they have someone already?

Well the way I put it is if u really love someone then you wouldent cheet on them. So that means that since they cheated on the person they don't really love them though the say they do.