I'm also disappointed with myself right now for an analogous situation, not sexual indiscretion but for unimaginably breaking the law (never did that before)... and now I'm stuck with the consequences in my mid 50s.

I doubt anything less consequential would have forced me to give up my cannabis addiction. I was also not thinking of consequences (and now over-compensate by obsessing about consequences). That combination with a mind altering substance can be trouble for some people, particularly people who lack insight at times and become impulsive.

Maybe that is not the whole answer but it is part of it. For you it is alcohol. As bad as you feel right now, it could have been even worse. It doesn't take much imagination to come up with worse scenarios. You dodged a bullet so far.

I'm sorry about your brother. That is not what you needed. He was only thinking of himself and not of you.