...kind of stuff happens to straight guys with the girls there too...he will want to come visit and will mention that before you leave..."maybe u can send me a ticket"...dont sweat it...buy him something nice if you are enjoying your time together, if u are really into him bring him over to visit..thai people are very friendly and while he may have ulterior motives if he wanted money he would have told you..as he knows you could leave without telling him..just go with it.