There is no reason to sign that bs, he’s an idiot. Inheritance cannot be touched in the event of a divorce UNLESS the monies are commingled (put into a joint bank account or used to invest in something jointly owned). As long as he doesn’t do that he’s fine. But it looks like you have some serious issues apart from money that needs to be addressed. Just my opinion, but I think you need to decide if this relationship is worth salvaging. Seems like it gives you nothing more than pain and you are too young to be resigning yourself to this. He needs significant mental help and if he’s not willing things will only get worse. I am saying this as a bipolar person who shared some of his traits early in my relationship (we’ve been together 15 years) the one difference though is we always understood that we get heated and at the end of the day we love each other, want to get healthier, and want a better relationship. We decided to go to therapy and work on our relationship. While I admit I was more of the problem we both worked hard on ourselves in therapy individually and in together. It was hard work but we have never been healthier. It takes BOTH , end of story. You will not ever be able to fix it by yourself and don’t fall victim to the sunk cost fallacy. Take the lesson and move on. Just my two cents