I work at a title company in New Mexico and our laws here are a little different. Even though New Mexico is a community property state, if the house was a gift from your parents and you have that documentation, in this state he is not entitled to any part of it unless at some point you put him on the deed as well. Check with a title company or a real estate attorney in your area to see what your laws are there. Even if you did put the house in both your names, it does not mean that you would have to give any part of it up - that is up to the judge to decide, but I would stand my ground on that and not give in.