Why do some people dismiss serious conversations by telling others to "get over it" instead of listening?

What are the chances of a cheater changing his/her ways? Is there any way that they can be helped so that they don't repeat their mistakes again in the future?
What is the salary of a politician after winning an election? Are their campaign funds used to cover all expenses and personal spending?
I can’t forgive myself, I’m having a hard time from someone I love, how can I move on when I know I’m at fault?