
Uke's insecurities stem from the fact that time and time again the men he had experiences with were either curious or had dating experience with women. His insecurity didn't just appear overnight, and yeah, it may be stereotypical but when you've been chucked out like you're worth nothing and just a "substitute for the real thing" some people would start to believe it to be the case. And the seme isn't really a different case, one of their convos were that seme didn't really know he was attracted to anyone until the uke. To the uke, that seemed like enough reason for doubt to fester, I mean, he might find someone else. And just a personal theory, its maybe because of that very uncertainty, and the lack of exploration on the seme's side that gave birth go genuine fear coupled with ukes previous exes experiences. ANYWAY, not saying that these excuse anything, I'm merely providing a perspective as to WHY he'd think that way. The queer community is very divided, as some who experience predominantly same sex attraction fear those who experience both sex attraction in their partners in fear of being abandoned. As this phenomenon is very common in spaces where queerness isn't really accepted, so often those who go back to what is seen as a socially accepted norm such as a heterosexual relationship are often driven to do so by fear of social rejection. Heck, a lot of queer people don't advise getting in a serious relationship with sexually curious and or experimenting people because it might lead to more bad than good.

y'all would get mad at the toilet scene but not when the seme is an abusive little shit... and like the toilet scene isn't even bad??? like mio and the seme weren't even dating or at a point in their relationship that warranted jealousy. Seme was still in the ropes of figuring out whether he was attracted to Mio and that scene gave confirmation!!! U guys act like this was a cheating scandal likeee even then y'all have weird double standards!!!! fake ass fujoshis and fudanshis....

This is so real. I actually liked that scene because it broke the stereotype of the bottom having to stay pure while no one bats an eye if the top sleeps with other people before the main characters officially get together. I can think of so many mangas where the top sleeps around while also sleeping with the bottom and no one cares.
these dumbass mfs.... i lvoe them