Thank you. It didn't feel right to me, the way he looked at it.It is absolutely incorrect that that only the principal portion of your mortgage payments would go towards your equity. You are entitled to a share of the appreciation as well.
You are unmarried joint owners of a property. You would not go to court the way that a married couple would go to court if they were separating. You would file a partition suit. If you could not then agree to a fair apportionment of the equity, the court would auction the home off and give each one of you half of the proceeds after the mortgage was paid off.