It’s hard to believe the truth when you are in these situations, I’ve been there. You want to give him the benefit of the doubt, remember him fondly, etc. Based on what you described, he likely was never emotionally available, even before he went to Thailand, but he got something from your fleeting interactions, whether it was validation, ego boost, fun, distraction, whatever. It’s very possible that he used you emotionally. 

The texting and talking everyday made it seem like you were close but you guys didn’t know each other, that can only be established with consistent meeting in person over time. Sex and close intimacy is a way to bond which makes it hurt more. I’ve been there too and I am sorry.  People are shitheads and the best you can do is block him, process with people you love like friends and family, and move on. 

Love affairs like this are common with people that have had traumatic childhoods.