This is an older manga, but the seme is more realistic in terms of writing (yes, this is a manga, I know it's not real). The uke on the other hand is just terrible, and I think he doesn't deserve the seme. I get he's concerned about his brother and obviously because his brother is a high schooler. I will admit that the seme was dumb to not be upfront with why he was texting the brother, but even after the misunderstanding was cleared up. He was still an asshole with the "any other man will do" bullshit.
To people confused about people having sex with others when they are in "love" with someone doesn't anyways mean cheating. For example, Person A is in love in Person B, but doesn't want to confess because Person B is straight. Person A IS ALLOWED TO HAVE SEX WITH WHOEVER THEY WANT. They are not obligated to stay a virgin or abstain from sex because they aren't in a committed relationship.
I thought the ML was already bi..? I thought he dated men and women prior??? Weren't there instances where he said a guy looked like his type? Plus, it felt like there was some underlying subtext with that one guy he used to game with, but I guess the writing felt like it was tossed to the side.
maybe hes still in denial
I think he's in denial + he's tossing attraction to men aside because he likes women