Many times we have no idea we're making a mistake until the negative outcome manifests itself. Sometimes we know when we're making that mistake and for some reason do it anyway, knowing there could be negative repercussions, knowing it could hurt people.
Why do we make those decisions? The ones we know are mistakes but for some reason can't seem to turn away? Especially when other people's pain will be involved.
I can only answer that question for myself, and I'm not really sure. If I were to guess, I think many times it would have to do with insecurities, stress, envy, anger, coping mechanisms. But it's not purposely. All on a subconscious level.
Then what can we do?
- Feel remorse
- Forgive yourself
- Move on
That's it. The rest is up to them. You can't pressure them to forgive you. If they do, they do it on their terms taking as much time as they need which could be a week or a year or never. And that may be hard, but that is what you've caused and you'll have to live with it.
Forgiving yourself is important. If you can't do that, you'll be a prisoner to this one mistake, and you will let it define you. You shouldn't have to pay for one mistake for the rest of your life(well, unless you've killed someone, maybe then). So forgive yourself, learn to like yourself again, and start over.