There's some nuance happening here. First of all, MC didn't mean to have an affair, especially when the boss initiated everything and the morning after they had sex, it seems like they were drunk the night before and MC looks horrified. In chapter two, MC even admits that he just wants them to go back to boss-employee relationship but it's hard after everything and he obviously regrets getting involved. And while I understand MC isn't out of the woods bc of these reasons, he clearly doesn't have as much culpability as the boss, but only ML really sees the boss as a predator unlike everyone else, including the boss's wife who only sees MC as stealing his man. Sis, your husband started it >.<
And yes MC may not be a squeaky clean person but there's clearly more to him than what you see at the beginning of chapter one. He was bullied when he started working too so it seems to have carried on with him. I think the manga will be about his growth as a person so you always need a Point A for that in order for Point B to be satisfying.
As for what seme is thinking, I have no fucking idea lol.
first couple really did a relationship %any speedrun but I'm happy for them <3