Kinda dumb.... when, you know, it's the responsible thing to, if acting as a guardian, not let your lust/interest in a person mean you'd kick out the person you're being a guardian of.
Basically, I'd have answered more "well, nothing is gonna happen anyways, we aren't even in any official relationship and I'm not going to kick out the person I'm acting as a guardian of just so I can get laid. If anything, I'd have called home and let her know I'd not be returning for the night, but no big deal."
Basically, that woman's jealousy is making her derp and he's responding derpily.