Can't remember

so this is pretty vague but its a yaoi I can't really remember but the seme was fat in high-school so he worked hard and got fit and i think the uke knew him in high-school but anyway they meet in work eventually get into a relationship and stuff and in one of the extras he tells the seme to stop working out cause he's always working out and so the seme stops and gets fat and he doesn't want to do it at all and the uke gets sexually frustrated and tells him to get fit again does anybody know it?