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I have been spending time with a person who has expressed that my daughter is an asset in a relationship, but we are not in a relationship . . . I should have been clearer.
The contrast between their views and my ex's is just a real tell.
Just don't let your guard down; talk is cheap, and anyone interested in a relationship would know enough to say the right thing up front about their potential partner's kids. But in the long run, when those same kid(s) become a hindrance to them, does their tone and attitude change? That's what you need to watch out for. Kids need to be picked up and dropped off; can't take weekend trips whenever you want. Can't stay out late. Gotta buy an extra seat, pay for an extra ticket, get more space, can't go to 21-and-over places, Etc. etc.
After I got divorced, I eventually (a year later) got into a new relationship. When she eventually met my daughter, it seemed to go extremely well; she had taken the time to research good ways to do it, and always made sure my daughter had treats or stuff to do at her place. Her and her family would always cite my commitment to my daughter as a positive and a sign of good character. They knew plenty of people that rarely or never saw their kids again after divorce.
We were together for four (4) years, and over time, her attitude toward my daughter got worse and worse. She would complain about my ex-wife's behavior, which was understandable because BPDxw was awful, but she would do it in a way that put me on the spot and tried to provoke more conflict. And in months where I had back-to-back weekends with my daughter she would complain "we just saw her." and other stuff like that. Near the end of it, she started openly picking on my daughter, which was an absolute red line for me, and we broke up shortly after that.