Can someone interpret this guy’s behavior?

Hopefully I’m posting this in the right category.

I met this couple in a group setting and noticed that the husband stared at me very intently whenever he spoke to me. It didn’t feel sexual because he was never flirty and only looked at my face but he did not interact with anyone else with that level of concentration, even his wife. We talked to each other as much as anyone else and he was always like this during our side conversations. We did not talk about anything extremely serious or interesting so it couldn’t have been that our conversations were so intense. It’s a minor thing and it didn’t make me uncomfortable but it was odd because he was so mellow with everyone else.