You're the problem. lol Amazon has lists for this. I had this same issue with my wife. Carts are for shit you plan to buy. It makes no sense for me to have to remove all of the bookmarked crap so I can checkout, especially since that defeats the original intent of bookmarking the items.

So I just created a list called Wife Shit and she throws it on there instead of the cart. Funny that we had this exact same issue. 😂

In summary, your wife is using the cart correctly. You're the one with the terrible habit here.