what an annoying gf
no wonder he broke up with her IRL
read this manga main comments, someone says so
Nobody in the main comment section actually said that, you probably misread someone saying "It'd be a shame if that happens" or "Haha I hope this happens because I'm jealous, normies explode" (accurate paraphrasing, some of those guys were being really petty about this after they discovered it was based on the author's relationship).
So, key points here: Yes the series appears to be semi-autobiographical (apparently mentioned either in later chapters as extra pages or in extra chapters or something), no I can't find anything that says the series ended because the real ones broke up. They still could have and that just wasn't made public on the platforms relevant to how the series was being promoted that anyone commenting on it here has checked. But it's just as likely that they're still happily together.
Schrodinger's couple.