My girlfriend cheated me and I killed her.

One is the pleasure of revenge, which is your first purpose, but will you really be happy? If you really love her, even if she cheats, you can still bless her, but you can't, so you don't have all the feelings for her. In that case, why kill her? You will spend the rest of your life in prison, which your parents and friends don't want to see. Your parents can do anything for you, including going backwards for your happiness. It's all feelings. Are you worth making them feel sorry for such a person?

The second is to repay my feelings. If feelings can be repaid, it is not called feelings. If you let her die 10 thousand times, your feelings will be irreparable. In this case, it is unnecessary.

You can be afraid of nothing, but you can see from your language that you care about your parents. Is it useless for parents to be pointed at and say that their son was abandoned and killed? Are these parents really failures?

What's more, if you kill her, she will be reborn as a human being in addition to the unparalleled loss of her life. There is no pain, but you gain more than you lose, and then you can hook up with your parents!