Revised Logline:  Enraptured by a pretty woman in a Chinese mountain paradise, an American business tourist sponsors her marriage visa but then faces a quandary when he returns to the US and she arrives at his home.  

Title is still under consideration.

Bit confusing to be honest. Is the assertive girlfriend the same woman who arrives on his doorstep?

Might be a better adjective than 'assertive' too - like demanding, or high maintenance.
And it sounds like the American tourist acts impulsively by proposing marriage while he's overseas, is that right?

Yes, he, the tourist, proposes marriage while he is in China.  That makes the woman the foreign fiancee.  The girlfriend is back home.  I was trying to be economical.  Thanks for your comments.

The story is a modernist take-off from "Madama Butterfly".

If I'm off base, I will delete this comment... I would not call it Yellow Fever. "Yellow" from what I know is a derogatory term for Asian persons.

AJR

I am glad you noticed.  I put it in quotes, for the time being.  It comes from the Navy Vet  sidekick character as a possible explanation for the protagonists condition.  In Chinese, Huang Bing.  Could go with something like  "Asian Fever".

Maybe:

After a vacationing tourist impulsively proposes marriage to a local, l small-town Chinese woman, he must face the consequences when his long-time American girlfriend surprises him with a visit.

Strong recommend against the title. I wouldn't use "Asian Fever" either. Spike Lee can do it. We cannot.

I think you should build on Dave's recommendation. The "After (x) happens, the protagonist must (y)" structure is always nice and clear because it matches the way the story will progress.

Thanks for the feedback.   I was just about to give in to contemporary sensitivities when I ran across the novel by author Toni Morrison, "Tar Baby",  So, that gave me pause.