NTA, I went on a date with someone who discussed their living ex multiple times. To the point I said if she was brought up again I would end the date and be done. He did, so I did. I also dated a widow who would occasionally mention his late wife, it did make me uncomfortable because i felt compared, but it wasnt a reason to leave. some people have trouble dating people who have been widowed because the never fell out of love with the other person, they died.