Honestly... I don't know what to tell you about all of this. What would be important here, at least from my perspective, would be to bring this situation to as constructive a conclusion as possible one way or another as soon as possible. It has all gone on long enough. You wrote that your post might seem one-sided because it's your version... and that is the way it comes across. This is all about you, how you perceive the various people in your life, & what you want for yourself.

It is true that couples can grow apart over the years. My wife & I have been married for 39 years. And at this point we have little, if anything, in common except for the fact we've been married for 39 years. (I don't know a lot of older couples. But, based on the few I am at least passingly familiar with, I don't think my wife & I are unique.) Of course, you are younger than we are. So your interests, & your perspective, is going to be different. However the point here is, I think, that the individuals in any marriage do change & tend to grow apart. And at some point couples simply have to make a decision with regard to whether or not to stay together. Hopefully that decision can be made in such a way that both parties are at least at peace with it even if one of them doesn't like it.

Will you end up spending the rest of your life with Tina? Maybe you will, maybe you won't. (From what you wrote, I'd say that may be a toss-up.) Might your wife just decide to return to Thailand? Of course I don't know. But it sounds as though that might be a possibility. There's a possibility here you may simply end up finding yourself aging & alone. On the other hand, perhaps you & Tina will stay together & live happily ever after. There's just no way to know for sure. I think all you can do is to decide what you want to do & try to bring this situation to a conclusion as quickly & as constructively as possible for both you & your wife... & also for Tina. Here are links to a selection of articles, from PsychCentral's archives, that I thought might be of some help as you contemplate your next move:

Burned-Out on Your Marriage or Relationship?

The Decision To Delay Divorce: 3 Ways Couples Delay The Inevitable

Want a Divorce? Stop the Emotional Yo-Yo and Be Clear About It

Are You Ready For Divorce? 8 Questions You Should Answer

When One Spouse Wants Out of the Marriage But the Other Doesn't

https://psychcentral.com/blog/the-ps...dult-children/

I wish you well...