Jealous? No. Sirius and his conquests happened to be exceptionally well known through out the school. Severus could name at least a dozen girls that Sirius had dated in their year alone. Someone evidently needed cover for their own desires. At lease Severus was serious about Lily Evans. And he did still love her.

But Sirius was dangerous. In so many ways. Severus likes that. And he didn't really care about gender. He never had. He just tended to hate people no matter what.

"What were you expected when I mentioned that I was going to study mushrooms, Black?"