I did the same. My parents had never met my boyfriend when we became engaged while at university in 1973. I hadn't really been going out with him for very long - weeks rather than months. We are still happily married - have been together for 44 years. I don't think my parents particularly warmed to him when they first met him, but, over the years, he has proved to be a very supportive son in law, and, now in their 90s, my parents realise how lucky they - and I - have been. Trust your son's judgement!