1. Rubbish. Adultery or any other reason for the break up has no relevance to financial issues. 2. Also rubbish. Child maintenance is irrelevant to the issue of financial provision. 3. Wrong. He invested his money in the family home. Current law is that the family home is to be split equally and he would not get his investment back. 4. If the property is owned jointly he can't sell without your agreement. Generally, a "separation letter" isn't valid unless you've had separate legal advice. He is telling you things that are wrong so as to get his own way. Do not talk to him again. See a solicitor immediately. I hope that helps. Please leave a positive rating so that I am credited for my time.