How do you live with yourself when you do wrong to someone?

Yes. They feel entitled.

@Aidolovemostofyourthoughts: Listen. The best you can do is apologize and assure them it will never happen again, and you might ask how you could make amends, but after that, if they refuse any of that, that is not your responsibility. Some want you to feel miserable forever. That's not warranted. If you've done all you can and they still won't accept it, time to move on. You've done what was necessary, and then some. You're not required to become a martyr for one mistake. It's not like you did it on purpose. Cut yourself a break. You said this person feels entitled. Sounds a little selfish to me. Carry on.