Ok, just imagine you are a man. So you don't need any women's clothes in the shop.
But what if you want your girlfriend to wear something special? Now you have to 1. give her money 2. explain what you want 3. you are still not sure she will get it
I suggest that you can buy clothes for anothert gender, apply it on dummy model, save as a set. While you are in room you can offer your partner to use your clothes instead of hers.