have you ever CHEATED by your GIRL / BOY FRIEND?

I had a boyfriend during high school years. We are very close with each other. Then one time we've gone a big arguments which is almost 3 months but we havent solve it yet. I admit my fault. Then one day he change. He became blooming as if in love. I taught because of me because he ask me to end up these gap. I became glad about it. Then one day because of our closeness I discover his evilness. He show me a picture he said his cousin but I feel different when I saw it so I investigate and through his phone a got a clue. I try to joke on him that he has third party I was shocked when he confested me. I feel really hurt and somehow insulted because Im not really the one that cause him happiness. But somehow glad atleast he is the one who gave me that important imformation.

When i was younger and in high school i cheated on a boyfriend and to this day i still remember it and how it was such a big mistake i did, as i still see him around today and seeing how successful he is and it bothers me that i could probably still be with him, but he has been with the same girl for years. But over that and have had many boyfriend since then. I can remember four boyfriends in my past in the last four years that have all cheated on me. I don't understand why guys would do this, and then having their friend tell them they are stupid because Holly(me) is really the best thing that ever happened to them as i have a good head on my shoulders and i know what i want to do with my life.