Funny you should say that.
Do you know the history of the bridegroom?
It seems that in less civilized times, a losing suitor would show up at the residence of the just married couple and attempt to steal the new bride by means of killing the groom before the marriage was consummated. It was the bridegroom’s duty to protect the couple while said act was being completed.
It is ingrained in men to perform the act regardless of the consequences. The only thing separating us from other animals is our discerning brains. If those get overriden, look out.
I believe you meant to say "best man."