Does it matter whether or not they know that you're not married anymore?
If they still believe you are, then I'd take it this isn't someone you typically share personal information with, so I'd say that it's up to you whether or not you want to set the record straight, and if so, when you want to say something.
You didn't do anything wrong by not saying anything. There were a few people at work I never said anything to about XABF and I breaking up, until about six months after the fact, and they were periodically bringing him up since they'd run into him.
I shared when I felt like sharing. It didn't really matter that much, otherwise.
When the one apologized for always bringing up XABF after I told him we were no longer together, I told him that was unnecessary, him mentioning XABF hadn't bothered me or I would have said something, but since he and XABF had helped each other a lot in the past I wanted to make sure I was comfortable with it before I shared it with him. He understood, and we still talked on a regular basis (up until they moved his office to the other side of the street, anyway - now he's hardly over here anymore).
What's important to
you? That's what matters here.