Husband is driving, who gets the front seat?

I was talking to an old friend today who is recently married. She was annoyed because her mother in law told her to sit in the backseat when the three of them were all in the car together the other day. She said that she, as his wife should sit next to him and his mom can sit in the back. I kind of just awkwardly agreed with her because I didn’t really know what to say but in reality, I wouldn’t be bothered if my mother in law wanted to sit next to my husband. I don’t think it’s that serious.

But I thought I’d ask CC because thinking about it now, it’s kind of funny to me