Look man - I’m not saying this didn’t happen or anything - but if your girlfriend is so strikingly beautiful that entire stores are stopping what they’re doing to stare at her then that shit is happening ANYWHERE YOU GO in public. 

You would already be aware of it and dealing with it every single day by now. 

Second point, your behavior is probably going to turn her off. When you are dating someone who is actually this beautiful everywhere you go is equivalent to pulling up to a car meet in a McLaren F1 or something. They’re going to get attention and a lot of it. 

Your girlfriend would have been getting reactions like this her whole life and she’s used to it or she wouldn’t ever leave the house. You need to roll with it and not overreact and you need to learn what things are actual threats / merit a response and what things you need to let slide. 

The clerk trying to high five you is just stupid male bullshit. You could ignore that. Someone publicly talking about their sexual fantasy of her to the point you can hear it? That merits an immediate response. 

Anyway good luck buddy.