Where I live, fathers still kick the tar out of punks who are too big for their britches. My son's friends refer to me as Mister - if they know what's good for them.
I never assume that I can kick the tar out of a man half my age, it's ludicrous. On the other hand, I once beat the holy crap out of a guy more than twice my age who was dumb enough to put his hands on me, over his daughter, when I was still young and at the top of my game physically.
Join the really real world where not all the fathers are capable of beating up all the boyfriends. My son-in-law for example could have beaten me up and down the street with relative ease just about any time he wanted to.