Responses
https://www.mangago.zone/read-manga/you_own_my_all/
He's not obsessed but total loverboy, borderline obsessed
https://www.mangago.zone/read-manga/dumb_husky_and_his_white_cat_shizun/
This is originally a novel but this guy's obsession runs DEEP. Not just fluff, there's lots of angst and you'll have to yell at him a few times before he realizes he can't let the other guy go, totally recommend
I'm looking for manga, manhwa, or manhua where the seme is obsessed with they uke in a good way, like he tian or hua cheng