This is such an obviously pointless padding to the story. If the writer had any self-respect, they'd have the MC sit the girl down, at the very least, and actually talk the talk.
People usually go back to their exes, when they think they have no options, they're getting older and are not as attractive anymore, and fall on a "safe", known option.
However, this motherfucker has at least 2 girls who actively told him that they're interested in him, and he's aware of it. So the MC has absolutely no reason to fall into the lap of a shitty ex.
I.E: This is obviously just for padding, for drama. Rage bait. Shame, the story actually did pretty well to avoid stupid shit like that thus far (i.e: stuff like: "what was that? I didn't hear you...?" times infinity.)