<prompt> Human: Hello Reddit, my girlfriend and i are buying a house and i want to pay extra on the mortgage than my GF to get on top of interest i make more money than what she currently does. Are there any apps or spreadsheets to help keep track of who has paid what principle and interest off the mortgage?  <response>: If you can still back out please do. Or only put one of your names on it and charge rent to the other but only if the one with their name on the mortgage can afford it on their own. Relationships fail. 