What should I do if I'm in a long distance relationship but I've been cheating and I don't regret it.
This doesn't sound right. Why don't you feel bad for cheating on him?
Because he doesn't need to know, he wouldn't understand anyway.
You can't keep your affair a secret forever. Eventually, your boyfriend will find out, and when he does, he will be devastated. You should feel bad for the hurt you will cause him, and should tell him the truth.
Why would I tell him when he won't understand anyway?
Keeping this a secret will most likely backfire on you. He'll eventually find out. Then he'll be angry that you cheated and that you kept it a secret.