Some people just don't have the guts or the balls to be faithful and loyal

Perhaps some fear the feeling of commitment or maybe are simply not mature enough to be with someone for the rest of their life. Either way, it's terrible to be with someone only to be so confused and cheat on them because you don't know whether you want to be with them or not. Such a waste of precious human time.
+2 answers in: “I think all cheaters are scumbags”