My ex from a long time ago (years) has texted me after each relationship he has been in since us ends, whether it's long or short. He will say little comments about our past relationship and want to see me. Last time, I finally agreed. (Nothing sexual happened) It was casual but he seemed to have this lingering pain in his eyes no matter how much small talk or laughs happened. He also lingered around. He then got into another relationship a couple months after that is still ongoing. No other guy I've known has done this so I'm confused. What does this behavior mean? Do guys normally do this?