Hate that i love you

Can someone tell me why is that guys find it okay to cheat on you and then say that they love you and still be with the girl they cheated on you with....how can you say that you love someone and do stuff like that. Do you not understand how that makes someone feels or what might happen to them... Then you wanna say that you sorry and still do the same thing... I'm tired of falling for someone who say they love me and then don't if you was going to cheat in me from the start then you shouldn't have gotten involved with me from the start