Responses

I'm not sure, I also tried matching the photo from nanapy(author account) where he posted their marriage photo, to the fitness guy (the one you mentioned), I think they do have a kind of Resemblance and same name too, but at the same time, I'm not sure if there are the person as same name and face of people exist
Bro they were talking about the real-life author himself, not a manga character.
Here’s the breakdown:
Ryosuke Nanazaki (七崎良輔) is a real person, not a fictional character.
He wrote a real autobiography, titled 『僕が夫に出会うまで』 (Until I Met My Husband) — about his life: first love, bullying, coming out as gay, meeting his male partner, and getting married.
The Twitter fight that happened at 4 AM was between Ryosuke and his actual husband (same-sex partner).
All that drama — the pollen in food, the nudes on secret Twitter, the cheating messages, and the brutal clapbacks — was between them in real life, and people caught it all because they were posting it publicly on Twitter
So yeah, this was not manga, it was a messy real-life situation between the author and his partner, spilling onto Twitter like a reality show.