If his reason was that he wanted to interact with his former classmates without having to concern himself with your enjoyment he would have said so. Instead he lied about his reason.
If he wanted to reconnect with a former girlfriend, he would have been overly concerned with his appearance of late.
If not then his reason is obvious, he feels you would embarrass him by either your appearance or your behavior. Men, in general, want to show off their wives/girlfriends.