feeling like you’re competing for their attention with the whole world
The shameless flirting. Strangers will hit on them right in front of your face like you don't even exist.
Coming from a straight man, the constant attention your woman gets from other dudes on the daily. They don't give a shit that she has a boyfriend/fiance/husband. They will hit on her like it's their job. Many will hover in the friend zone waiting for you to fuck up so they can make a move. It's a constant and never ending barrage of men.
Dating a beautiful woman is not for the faint of heart. You better be secure in yourself and the relationship.