Hmmmm got a feeling this isn't going to be a popular thing to say, but.....nuts to it.
MissAna is completely right. There is a huge difference in attitudes and mindset between Thais and Pinoy. I can only guess the two are compared because they are from SE Asia.
I spent some time in Thailand, I dated a lady there. I got to know the mentality of both men and women, and some of my ex's friends worked in the bars..........getting to know what they really think was quite an eye opener.
Friend of mine owned a bar there with his Thai wife, I made a good few male friends..........heard some right stories, of men who had lost millions. Men going over, thinking they had met some love, they build a house together, then one day all the male relatives turn up, barricading the way there "she doesn't lub you anymore, go"
This is very common. The attitude is best summed up by the in joke there "The currency is the baht, and relationships here are all abaht the baht"
It is a terrible thing to generalise, but when you hear the same story again and again and again........you get to see a pattern.
Try googling cheating pinoy girl, and you'll get a few results. Try googling cheating thai girl - and the internet will almost go into meltdown.
Plenty on both sides though. Frankly, if something seems dodgy, then it probably is.
OP you know what you need to do about this, I don't want to see you taken for a ride by anyone and suspect you have already decided before posting this -or know deep down the right answer.
Just do what feels right, after all, you know her more than any of us