I am sorry that you continue to feel sad that your H left you and wonder what he is up to. Its completely natural that you would feel that way, after such a long R and the frankly cruel way he left (to not even have a friendship with you).
I dont think you can assume anything from him still living in Thailand with her. They may be having lots of fun, but they may be argueing..my Dad visits Thailand alot and he has said you can live very cheaply there (£1.20 for a restaurant meal) and also, it is very beautiful. But.. he M her. Is there any way that you can work on your acceptance of that?
I feel you need to be very busy and distracted to get you through this tough period of your life. What can you throw yourself into to help you do that? How about going back to college? You can retrain and meet new people then. I have felt much much better since I have been very busy, doing 10 hour days, not sitting around the house so much as I used to. You just need help to heal NLT.