>>22323997him affecting her mood has no bearing on whether she broke up with him or not lol
you're ignoring so many of her offhand comments she's made over the past couple of months about him not putting in effort into the relationship, that song that reminded her of not getting out what you put in a relationship, being "done" with assholes, etc. etc.
she got tired of being the only one putting in effort and dumped him. he got blindsided by it and is running away to japan