I think my husband may have overheard my conversation

I'm worried about something that happened on Monday and I could really use some advice.
My husband and I have been married for a little over a year. Our life together has been really really great. (We recently started talking about having a baby!) 
Anyway to make a long story shorter, when we were dating I realized that he was, let's just say, less experienced than I was. I didn't want him to feel awkward or make things weird so I basically toned down my experience. It was not a big deal and I knew that he was my forever man.
This past Monday we were at a couple's home for a party. There were a bunch of people there - some we knew, some we didn't. Anyway, at some point I was in the kitchen with my girlfriend - she and I go back forever. We were both a bit tipsy and she started gossiping about a guy who was there. That guy was a guy I "dated" in the past. It started on a physical level and never got serious. He was all about the physical and all sorts of edgy (he liked the bum).  One time he convinced me to try to bring my girlfriend in.... which I did...  Anyway, she brought that up and was all giggly and asking if I remembered.  
I think, but I'm not positive, that at some point, out of the corner of my eye I saw my husband. When I turned around he wasn't there. I asked my girlfriend if she saw him. She said no she didn't and that I was imagining things. Anyway, the conversation ended right there and then. I got really worried that he may have heard us. I don't know for sure though. And if he did, I don't know what and how much he heard. When we got back to the party he was there and seemed OK.  On the drive home though, I thought he was kind of quiet but I wasn't sure.
I've been stressing ever since. My husband does not know about that guy at all - let alone the stuff we did together. He also doesn't know of the sorts of things I did in the past.  In the last couple of days he has just not been himself. He seems a bit distant or distracted or something. So I'm stressing that he did overhear.
I just don't know what to do right now. If he did hear, maybe I should say something before he does. Is that a good idea? And if it is, how do I bring it up and what do I say? Or should I let him bring it up? What if he doesn't bring it up? And then there's a chance he didn't hear and I'm just being paranoid and I should just keep my mouth shut.
I don't know what the best thing to do is. I would really appreciate any suggestions. Thanks.