From an “evolutionary” standpoint I think it could be said that it’s semi-normal for an adult woman to be with a 15 year old boy.But,of course,not legal.
I don’t know about that. Probably more “normal” for an adult male to be with a younger wife. That certainly was the norm historical. Males do have an evolutionary instinct to share their seed at the soonest possible time and before another male does, IMO.
Don't know if you're male or female but talking from a purely biological standpoint one could argue that anyone who's reached sexual maturity (usually somewhere around 15) might want to be with another who had reached the same maturity.