I think he’s cheating

So a few weeks ago my man and I were fooling around... tmi but I was sucking his dick and it sounded like he started to say ‘oh, jess’... I brushed it off like he was saying oh yes. And now tonight, he started to tell me a story and said ‘I’m not kidding, Jess’ and barely finished the name before I said Jess? And he was like I didn’t say that... lol he does work with a girl named Jess, she’s married and has a kid. But I never pegged them as hooking up. I’m stressed.