My sister's boyfriend cheated on her and I punctured his tire (keyed his car too), fair?

With my cousin's help, I punctured his tire and keyed his car. He cheated on my sister and she obviously dumped him but has been sad since.

I gave him a flat tire and he couldn't even make it to work, lol. Is that fair after what he put her through? He doesn't know it though.

My sister's boyfriend cheated on her and I punctured his tire (keyed his car too), fair?
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