My fiance and my 17 yrs do not get along. We have 3 kids together and we are going to build a house together. He said my son is very disrespectful and will not listen to him. There was a point when my son tried to fight my fiance, he has two more yrs in school. What do I do to mend the situation? He is not his daddy., and he said he cannot move into the new house.