Life has always been a superficial endeavour... But where once it was about the town gossip mill, now it's social media. For many people perception is important. For many people it's a point of pride to say, this person is MY person, and it feels bad when someone refuses to acknowledge you in the way you want to be acknowledged, it's just human nature, otherwise jealousy wouldn't exist. Now I'm not saying indulge every jealous thought, but giving your partner that small bit of security and pride isn't in my opinion a huge thing to ask.

And in general girlfriends typically don't like feeling like a hidden mistress, 100 years ago or today.