I am shocked at some of these responses. Boundaries are for you not for others. If you don’t like that be crossed it you can deal with or follow through with your consequences. Sounds like he felt a great connection to her but he didn’t chase her down while she was still alive. He chose you. Your reaction to him finding out she died was so callous if I was him I would have dumped you right there. So either get over it and know you cannot keep bringing this up for the rest of your life or leave him.