I met this guy and I ended up cheating on my girlfriend with him.
Do you think that was the right thing to do?
Yes. I didn't know if I would ever get the chance again. So, I took it.
Cheating on your significant other, no matter the gender, is still bad. You can do lasting damage to a person's trust in both you and everyone they meet in the future. Have you apologized for cheating?
I don't care about her trust.
If you don't care about her trust, then I think it's time to just end the relationship. If you feel no remorse and don't even feel like you need to apologize to her, then the relationship should end so you don't hurt her any further. Staying in this relationship will just cause her more pain down the road since you are likely to cheat on her again and she will eventually find out.