Don't let anyone tell you they're jealous because of something you've done. They're simply not confident, either about your feelings for them or about their own self-worth. That said, it might be time to look around for someone who'll show you admiration in a more flattering, confident way. Say, by taking you out to dinner, packing you picnic lunches and holding your hand across the table, no matter who's sitting at the table across the room. There. That's better already, isn't it?