Why in our culture do most women feel obligated to wear wedding rings while it seems that it's optional for men?

it seems like for men, wearing wedding rings is optional, whereas when a woman is married and does not wear one, it can be an issue? By “issue” i mean it’s something people may ask her “where’s your wedding ring?” Is it that women want to show they’re taken, while men may not want to? Or is it just that we have been doing it this way without question?

I am just curious – this is nothing pertaining to me (I’m not married!).