Having recently gone through a divorce I didn't want, and subsequently spending a lot of time in therapy learning many skills I didn't know I even needed, I find myself surprised nearly every day by how incredibly unprepared I was for that relationship.
I've learned more in the last six months about attachment, communication, and emotional management than I learned in my entire life before that.
Furthermore, none of the people in my social circle seem to have received any of this kind of instruction before, either. Nearly all are middle-upper to upper class with stable backgrounds. So, I don't know who's getting any of this kind of info from their parents or peers or any non-professional setting.
Learning all of this earlier in life might not have changed my particular outcome, but it sure would have made the intervening time better.
[Edited for spelling]