You can get a little jealous

You don't like it at all if he looks at other girls, and if he pays your best friend a compliment it annoys you a bit. Otherwise, you don't have a problem with jealousy. You keep your eyes and ears open just in case, but otherwise jealousy's not a problem for you.

All you need to do is take care not to let the slightest hint of a problem turn into a jealous obsession.