Why is my middle school son like that?

My middle school son keeps coming home swapping outerwear with his female friend. He has a very close female friend in the same class, and she asked him to swap clothes. The reason is that she says my son's clothes smell good.

According to the homeroom teacher, both of them have good feelings, but in case they start dating and then break up, it might be awkward for both of them, so they haven't confessed but are staying close.

Every day, I come home wearing my female friend's clothes that don't even suit me, and I have nothing to say about it.