Reading between the lines of the interview, he comes across as having had lots of not very serious relationships right up to the age of 40.
He refers to his sheltered upbringing and wanting to 'experience' a lot once he was able to. He also says he was 'complacent' suggesting he didn't get his head in gear about being a father until the pool of women available was much smaller.
It sounds like he was sowing his wild oats, as they say, rather than settling down. And then when he started thinking about having children in his 40s, he found women his age already had some or didn't want any (more.)
I have a couple of male friends who don't have children. One married late in life to a woman with 4 children already, another married (again) to someone who was that little bit too old to risk having a child.
They don't really regret it because like the man in the feature, it was never a priority and if had been I think they would have made different like choices.