I'm sorry I can't give you any definitive insight into this situation. However I noticed no one had replied to your post. So I thought I would.

My limited understanding of narcissism is that, for a narcissist, everything is about them. They believe they, & their needs, are of primary importance. Plus they lack empathy. You & your ex are divorced. So there's nothing about your relationship that is going to result in any payoff for your ex. Likewise, your daughter is from another marriage. So there's really no payoff for your ex there either. Consequently there is nothing for your ex to gain as a result of answering your e-mails. At least that would be my "take" on the situation.

Here are links to 3 articles from PsychCentral's archives on the subject of narcissism that may be of some interest:

https://psychcentral.com/disorders/n...ality-disorder

https://blogs.psychcentral.com/liber...-a-narcissist/

https://psychcentral.com/blog/the-da...s-narcissists/