I'd not want him to get into any physical confrontation at all because if I had a boyfriend, that would mean he is gay and gay guys make lousy fighters!
20 years ago, the "Tarzan" in me might have prevailed and pound on the guy like a silverback because I don't fear anyone, size of the other guy doesn't matter to me which I think is not true for most other guys. If I see red and get in the "Terminator" mode, things get ugly (for the other guy).
I typically end up feeling awful after I come to my senses later on.
Since I know this from personal experience, I have been developing myself mentally to control my temper and over the years I have gotten pretty good. After all, the angrier a person gets, the lower his IQ gets.
Nothing like losing self-respect because you got angry and did something that you know in your soul that is not really you. The more intelligent and civilized side of me would say "Really? Shame on you! Can't you be better than a caveman?"
Imho, the real strength of a man should be measured in how he controls his violent, destructive, hurtful urges.