I don’t think that is the reason he asked. It was the fact that she butt dialed him and he heard part of the conversation with his wife getting in her car with another man. Why wouldn’t he ask who she is with? She was evasive when asked.Sorry, I did misread that part.
By the way, the recent she tried to avoid telling you the guy's name is because it's embarrassing for people at work to know that your husband is checking up on you and quizzing you and doesn't trust you. You're just setting yourself up for the "old ball and chain" comments, which can undermine your authority at work. Save it for when she comes home.