Draco was your ex boyfriend. He was VERY possessive and obsessed with you. Every boy who dared to approach you was hexed into obvlion by him.

Draco came from a very rich and powerful family, Snape was his godfather and he didn't really like you.

Everyone in school knew not to disrespect him. You were his and only his even after the break up. That's why boys didn't risk approaching you.