Apparently, she mentioned the situation with her jeans to The Schwarz and he knew why this was! It was such a cool trivia fact to find out, that I just had to share. Apparently, if you go back in time, wealthy women used to have someone else dress them. So the zipper and button was on the opposite side to accommodate a right handed person that was dressing someone else! Fancy women's pants have retained this for some reason, even though women tend to dress themselves today. This also explains why men's pants never have the button and zipper on the opposite side because they always dressed themselves!
I thought it was a pretty cool fact to know, so a big thanks to The Schwarz for sharing his knowledge on fancy pants!