I came into the relationship with my own car. My ex did as well. Neither of us had car notes. Since we were living in a city at the beginning of our relationship and only needed one car, we both decided it made the most financial sense for one of to sell one of the cars. My car was in a lot better shape than my ex's so we both agreed it made sense for my ex to sell her car. (My car was new ish and fully functional, while my ex's car needed a lot of work. It was purchased used for like $2000.) We both shared all expenses on my car and both used it a about equally. Fast forward a few years and we both move to a house in the suburbs together and needed a 2nd car. We signed a 3 year lease on a car together and both shared the 2 cars fully, including insurance and expenses on both cars. In my mind, I was doing my partner at the time a favor. I had a car but wanted to help out with the lease payments because we were together.

Unfortunately a few months after signing the lease, we broke up. So now I am on the hook for these car payments for a car I don't need. My ex wants us to continue paying for and sharing both cars as we had been doing when we were together. I think this makes no sense as we are going to be living separately. I think my ex should completely take over the lease for this car. However, We did lease a car that was more expensive than what my ex would have paid on her own since we could afford more together. If my ex can't afford the lease on her own, I think the only fair thing is for me to pay the difference of what she would have paid on her own and the cost of the lease of this car.

Whenever I talk about this and say that I already had a car and was paying the lease to help out my ex, she just responds by saying, "I had a car too and I sold it because you had a car." Like, I didn't force them to sell their car. It made the most financial sense for her to sell it. She would have spent more on insurance in two years than the car was even worth and wouldn't have been using it at all.

What is the fair thing to do here if we can't get out of this lease? I feel like my ex isn't being fair to me but am I missing something here?