If they were in the process of getting over someone else or just weren’t ready, does that mean their initial interest wasn’t real? Could things have worked better at a different time?

I met someone once who was very interested in getting to know me. Paid attention to every bit of the convo and remembered things about me. Respected boundaries including the pace at which I wanted to take things. Acknowledged feeling like we were clicking. It was in fact my idea to casually date (including seeing other people at the same time if either of us wanted) and see where things go. And he agreed with even the hopes that more would come of us. But in the end we didn’t date because someone he was trying to move on from resurfaced, and he ended up dating her and exclusively. After that, I would never reconsider dating even if the chance arose in the future. But I can’t help but wonder if the interest I thought he had was real, and if things would’ve been different had we met when he was over her.