Yeah I wholeheartedly agree with your point. I'd also like to point out the parallel the mangaka did but it wasn't mentioned anywhere later on how ritsu's friend who died got cheated by her partner who also threatened to leak her nudes and how ritsu did the same(infidelity and threatened the MC with their sextape when he stalked him)
I wandered what went through ml's head or whether he even realised the similarity.
i noticed the parallels of that too, so in the scene where she explained the breakup and nude leak, i was hoping to see his dialogue or facial expressions reflect his regret in treating someone he loved like that too, but unfortunately no hints were dished out that he drew that connection. wish the author went into more depth with his reflection.
Honestly, I think Ritsu intentionally cheated on Masumi unlike his previous flings where he just had a casual relationship with everyone naturally.
It's like you always get the short end of the stick, so when you finally luck out and get a good one, you get scared and revert back to what you're used to even tho it's bad.