Most Helpful Guy
It means exactly what he says, he doesn't want you to dress sexy. He must have his reasons.0
Most Helpful Girl
He doesn't want to get into a fight when other guys hit on you. I say go for it though. Might be interesting.2
He has yard or house work planned for you.
I guess not revealing. So just cover up and that should do it.
He may not want other guys checking you out
What were you doing when he said it?
He doesn't want to you to dress sexy
he does not want you to dress revealing
It could mean he doesn't want other guys giving you attention... among other things. Needs more context.
He wants you to dress modestly probably so other men don't drool over you
It means he's a jealous, controlling bitch.
It means he's being controlling