This feels like a sequel, but the previous chapter isn't here. Anyway, if MC is smart he will accept the open relationship she is offering and buy some condoms. There is no evidence that she broke up with the president. On the bright side they have both learned new tricks in the 2 months they spent apart.
Male MC should honestly get the fuck away from this chick if he is looking for any semblance of a real relationship, she clearly is not into being loyal to anyone it seems.
Expanding on that, seems that Yoshino is the polar opposite of Shuu in regard to relationships; he seems to want monogamy, while she casually and willingly gets together with anyone and everyone. Despite his misgivings (or perhaps he was 'backed up' for a spell), their physical compatibility is still there, but it's not enough for him to lose himself over her, as he might have before.
And by the close, it seems she's the same old former lover (at least in his opinion).
Sometimes one just has to shrug their shoulders and say (like the gentlemen from Hollis, Queens):