I wonder if he was lying about being total player and dating all top girls in HS for fun. At least hope so that he isn't just a playboy...
From being Aikawa junior he should know Yui-chan from her student days and maybe they even went school at same time as we don't know theirs age.
It would be funny when they both realize that she was book worm and he was shy guy both of them being toys of Aikawa-sensei.