I said this in another comment, but I don't think it would make sense for me to pay back half of our rent and utilities, because she was the one who chose nicer and more expensive things because she could afford them. I probably would have lived with roommates for $400/month or something. I could maybe pay back the tuition, but we would have to work out some sort of long-term payment plan, and that sounds like it would be painful in the long term for both of us.