At what age is never having been married a red flag for men, for women? Is there a difference in your mind, and if so, why?

I was having brunch with my cousins and one if them is in her late 30s and she started dating a guy in his early 40s. Both of them have never been married. She was mentioning how she thought it was a red flag that he's never been married and we all just looked at her like "seriously, you're gonna say that?". For context, all of us are in our 30s and she's the only one who has never married. She tried to say that it's different for women and we just started giving her tons of shit to the point where she left early. What does PPD think?