Just call it youth ╮( ̄▽ ̄)╭
I don’t understand what you find so confusing about the uke sleeping around since that is completely normal for some people who isn’t in a relationship. As for the seme falling in love too quickly. I mean let’s be fr here the seme is a high school boy it’s really not surprising to see a high schooler falling in love with someone quickly. Most young people and sometimes adults fall in love quickly even for the silliest reasons. (1 most common reason is their looks.) To sum it up it’s basically “love at first sight”
First story was confusing as to why the uke slept around with men. Also the seme fall in love too easily.