I'm in my fifties and I always wonder about those never-married guys at my age. One of whom is my most ardent suitor at the moment.

It's definitely a red flag for me so far as dating goes. Are they so socially inept that no one would marry them? Were they a commitment-phobic player - and still are? Low testosterone???

As for my current never-married suitor - his story seems to be as follows:
Traumatic breakup at thirty after a five year serious relationship - he had his reservations about the relationship, but when she left he went kinda crazy. Then I think he spent most of his thirties dating around and drinking too much and trying to get somewhere in his career. Then in his forties his family's health fell apart and he returned home to help - father died of a prolonged ugly illness, then mom got sick and sister had a bad stroke.

Some bad breaks, but obviously, someone who was more motivated to be coupled up and a little stronger emotionally would probably not have made the same choices.