Help me gain new perspectives on this

I’m recently going through a breakup with a guy (33M) i’ve been online dating for the last 3 months. We first met on a dating app when he was visiting my city (he’s traveling full time at the moment) we hooked up and kept in touch ever since. I had never been in a casual relationship before. The concept is just so bizarre to me.

Anyway, he was traveling to a different country, hiking all day long everyday and was still texting me actively, flirting with me. At one point he proposed that we should meet in Bangkok but then i denied saying it sounds risky because then catching of feelings things will come on the way. And he told me “already too late for that” i think it’s at this point i started catching feelings for him and started romanticizing him. Pretty soon he decided to fly back to my city to see me. Which i genuinely didn’t expect. Fast forward, he comes to my city, we spend 6 days together, laughing, playing, exploring. He paid for EVERYTHING. I cooked dinner for him once which he really enjoyed.

And he took me on a surprise date for me to experience things i have never experienced before. Like golfing and bowling.

On our last day together, i went through his phone while he was in the shower and found out that he was looking for dates and pretty active on 3 dating apps consecutively while he was in the other country flirting actively with me. It genuinely broke my heart. I almost didn’t know how to react and didn’t want to say a proper goodbye to him but i kept my cool.

After he was gone, i was left miserable, the memories of him haunted me. The places that we went together, the roads and we rode motorbike, everything was killing me. Although we were still texting, like we always do, he was giving me updates and telling me about his day very intensely. i thought it would be better for me to come clean with him about what i really want from this. So i did, i said at this point in my life, i’d much rather be in a committed relationship than in situationship with someone i cannot keep. And he said he really likes me , he finds himself looking at my pictures all day which brings him joy. that i bring something in him but he is just not in the place for anything at the moment.

So i called it off. The whole thing was short but intense. The breakup was painful. I suffered for quite a days to even get off the bed because i miss the routines. We were texting each other everyday for 3 months and now we’re in no contact. I’m finding it hard to keep a positive outlook on the whole thing because it happened and i felt so loved for a while. Rather i just feel disappointed and sad.

Help me understand why do guys act so boyfriend-like when they’re not looking for a serious relationship?