Me (28F) and this guy (33M) stopped talking after his trip to Brasil, and I really want to know why you men act this way?

I have been talking to this guy since November of last year, we met through a dating app, we liked each other, we exchanged our socials, we started talking, we were into each other, had a lot of things in common such as we love the same football team, we're both religious, etc etc. I personally liked him, he was the type of guy I would fall for, communicative, smart, hard working, calm, ambicious, a gentleman, he was always asking about my feelings and looking for ways to make me feel comfortable, etc, overall, a "green flag" or so I thought. The only issue that was there, was that we live a little far away from each other. The thing was, we live in the same country, but in different cities.

I originally was planning on moving to the city were he currently lives in this summer, way way before knowing him, so we should have been apart for just a few months. Because I was working a lot and wasn't able to travel to meet him, also I have high standars and didn't want to be the one to travel, I wanted him to make the effort, soo he did. He asked me what days were the best for me, booked flights, airbnb, he came, we spent a great 3 days together, there was chemistry between us, I felt calm near him, I even celebrated his birthday because it was a few days later and gave him a birthday gift. We even spoke the last day about how we were feeling about this and we both were looking forward into wherever this was going and I thought we both were on the same page. Until, it came the day were he had to travel to Brasil with his bestfriend, then the last time I've heard of him was when they got there. Then he stopped texting, calling and even reacting or liking my stories on IG, but just watching what I was posting.

I didn't text him back either, just because at first I didn't want to disturb him or whatever. Now he should've been back to our country from his trip, he haven't texted or anything, yet.

A very important thing I might add, is that during his trip, by coincidence I discovered that he wasn't just with his friend, but he was with a local woman with whom he shared his hotel room and probably something happened between the two of them. The issue with this is not that I have a problem with this, I know we don't have anything between us, but I clearly spoke with him about whether he wanted us to be "exclusive" or not, and that I wouldn't mind him or me talking to other people until we were sure of each other, and he INSISTED on being "exlusive" and not playing between different sides.

He even said that he was READY to delete the dating app because he said he liked me a lot, and so we did, we both deleted the dating app. So for me, it's more of the "pact" that we had and his word that he couldn't keep than any other thing.

Now I have had proceeded to delete his number, and deleted him from IG, because why would I keep someone who doesn't even bother himself to text back. Although I am very confused because of his behaviour and I really want to know why would someone do this? Why do some men act this way?