Thai women are amazing, but they simply can’t be trusted to be faithful when you are not around. The hotter she is, the less she can be trusted.
This shouldn’t bitter your opinion of the women in Thailand, this should only make you more aware of what’s really going on. Enjoy them while you are in Thailand, and enjoy talking with them when you are away from Thailand. But be realistic about what is really happening.
She will take great care of you while you are in Thailand, but when are not, she will find another.