It's never happy when something doesn't work out, but I'm sure it feels better to have an idea where his tolerance level for drama is. I'm glad he read this thread and was objective instead of defensive, that always bodes well in my opinion.
I understand worries about trusting a partner's judgement - usually the people my husband dates have been great but he has a history of trying to play the white knight. That's mostly been solved by making two of our agreements - we each go dutch or alternate paying on dates with our partners, which helps keep finances in check, and dates have to be at least willing to make equal effort to travel to meet out/take turns at who's house a date is (which I requested because he has a car-less close friend and was also spending time with a car-less interest where it was adding 60-120 minutes to his commute to pick up and/or drop them off at home).
He has been disappointed a couple times when he was interested in somebody and they would've required giving more time or money to the relationship than these agreements allowed. One woman wouldn't take the bus outside the city limits to meet him, and though tempted to make an exception I didn't, and I'm glad. Hmm why all this babbling of mine? Maybe if there are certain things that you or your husband really want to avoid there are agreements that you'd be comfortable making that wouldn't do a lot to limit partner choice, but would potentially keep the most problematic issues from happening. No idea if that would be useful in your situation, but I thought I'd mention it.
Happiness will never come to those who fail to appreciate what they already have.