I don't think the uke was cheating. It's pretty clear in the beginning he wasn't gay but gave the younger guy a chance. 2nd, he can have friends and meet any girl he wants unless sexual. The seme is clingy and that's why uke's colleagues kinda get suspicions. He doesn't wanna colleagues to know he's dating a guy. It's his choice to keep it secret from others. It's not like they're close. He can't even stay out hanging with friends cuz his bf gets restless. Leaves him no personal space. I think both guys are not wrong in any way. One is obsessed and manipulative though cuz of his past and also having no friends.
I kinda get where MC's anxiety coming from damn I hate that cheating ass uke