Cheating

I don't get it. SO cheated on you and you found out. SO say they are sorry. It was a mistake, etc etc. SO want to work it out. To fix the problem. AND This is were I am comfused...SO care or they don't? Why would SO want to work it out if they DON'T care about you? Or beg for your forgives? I know a lot of you would say they "don't care about you" since they cheat but WHY would they want to fix it or want to be with you of they didn't care about you?

I just want some clarification besides of "they don't care about you."

Thanks