I agree with Rive, though I get the urge to analyse his behaviour. It seems to me you want to analyse his behaviour because of how intrusive he was about asking you? I’ve been asked why I’m not married before as well (usually by total strangers) - certainly it’s not other people’s business but it does throw you if it’s asked out of the blue, especially as some are still judgmental about single/unmarried people. Sometimes people are asking because they want to pick a fight.
All that said, he sounds insecure and confused, but it is his job to figure things out.