It wouldn’t be an automatic deal breaker for me. My main concern would be whether or not that person could be lived with. Someone who is 45 and has never been married or had a marriage-like live-in relationship, would be very used to living by herself, I would think. How will that person respond to sharing a bed? refrigerator? bathroom? How much independence will she be willing to sacrifice? Again, none of these are automatic disqualifiers. They’re just concerns, the same as if the girl was 18 and I was wondering, “how much does this person really know about being out in the world and taking care of herself?”
On the one hand, this may say something about never-marreid people aged 45+. On the other hand, this may say nothing at all about such people, and may say a lot about your social circle, your prejudices and weirdly skewed perceptions and/or recollection.
Maybe if you were more supportive of the troops …
Just because someone has lived with a romantic partner, or been married, does not in any way guarantee that person is going to be easier to live with than one who hasn’t. I say this as someone who just married a guy who had 2 previous relationships before me, both of numerous years, both of which involved cohabitation, and he still hogs the bed, leaves the toilet seat up, and throws his dirty socks on the floor. Obviously, if those are our biggest issues, we’re quite lucky, but still… previous experience with cohabitation is no guarantee of success. In fact, it’s proof positive of previous failure.
Whoever you date is going to have issues, which you are going to have to find out by trial and (possibly) error. At least someone who’s single, kidless, and never-married is guaranteed NOT to be carrying around the baggage of one or more divorces, a kid, etc. That would be quite a relief, I’d think, to the potential partner. How it’s a neg or would be a dealbreaker for anyone rather boggles my mind.