A guy said some inappropriate things about my girlfriend…

The best part is that I know of the kid cos we went to high school together. I have never liked him based off of things he did back then.

Part of me really wants to let it go and another part really wants to approach him! I have a temper so approaching him wouldn’t be the best option!

I just don’t understand some guys.
I am a guy and I don’t act like he did.. It is not necessary or appropriate!