Second Cherry
Simple and realistic. Two were straight before meeting and dating each other. Uke is older, it shows how difficult it was for him to be able to take it during sex instead of the usualy experienced Ukes.
Furenaide Ritorusuta
Borderline incest because older uke has raised the much younger seme since he was only 8 yo. They're not related by blood, since the seme is the son of the uke's aunt's husband from a previous marriage. A little weird still, but their love is genuine for sure.
Imitation Play
Older uke is a bar manager. Falls for the younger bartender who’s the devoted type, but since he’s straight the uke decides to hide his feelings. Ofc they slept together when the seme broke up w his gf and mutual feelings. Reminds me of Shizuma and the fox eyed pretty uke from another manga, similar straight x gay concept
Suezen Kurau wa Otoko no Tachi
Two playboys, one straight one bi, fall for each other through bodies first This is in desperate need of a 2nd volume. They BOTH need more character AND relationship development. Everything seems too shallow right now for it to end here
Retsujou no Meikyou