How bad is it to cheat and don't feel too much guilt nor remorse about it?

We all just finished our junior year of HS on June 6th. I'll be turning 17 on June 29th. How bad is it to cheat but not really feel much guilt nor remorse about it? I mean yeah it's wrong, it's bad but it's not like you committed an actual crime such as drug dealing or rob a bank.

You still love your family, close friends and pet. You just don't feel guilt nor remorse for cheating on a HS sweetheart.

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Just a quick update:
I'm back to being all alone with just my dysfunctional parents, few close friends and my GSD pet. I broke up with my boyfriend and simply told him I wasn't interest anymore, no further explanation given. Though the other guy didn't like it when I broke up. He was ok being the secret date. Now he doesn't want me anymore. I feel so bored and empty.
How bad is it to cheat and don't feel too much guilt nor remorse about it?
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