(Spoilers)I guess I am not as enlightened as others b/c I..

You are forgetting that all of what Tashi saw was a "dreamland" caused by the wine, in his case ending up more of a nightmare because he killed someone. The point of that was to show that maybe Dondup's dreamland is the dreamland he thinks it to be, or maybe it will be the nightmare Tashi's dream voyage ended up to be.

Either way, both characters found themselves back at the crossroads, deciding what their next move in life would be - Dondup's choice between America and Sonam, Tashi's choice between continuing his tribal education or giving up.

That's the way I see it anyway. Hope that was helpful

I love this movie. Let me try to answer your question. I think the parallelism is not the adultery but the line in the movie: “What you hope today becomes what you fear tomorrow.” (I can’t remember the exact wording.) And the main idea of the movie that everything is merely an illusion (or a dream) while the protagonist takes it so seriously that he almost believes it is true. Both of them apply to the young man Lhakpa in the fable and Tsewang, the official who wants to go to America.

Lhakpa, the lost man in the forest who falls for Deki used to crave beautiful women when he is in his village. But when he gets what he wants, everything becomes torture —he doesn’t even know if the poison can put the old woodman to death. When he sees Deki dies in the water, he tears painfully but this authetic experience to him is just his younger brother’s magic trick.

Tsewang is eager for catching the bus originally but after meeting the father and daughter and with the monk’s elfish words that “I think she likes you.” and he having a talk to the young lady, somehow he seems to change his mind. Later he kind of hopes that he can stays with them. Doesn’t this match the notion that “What you hope today becomes what you worry tomorrow.”

In short, this movie conveys an important concept of Buddhism: Mind creates and decides all kinds of situations you are and about to experience. Mind is magic and mind tricks you. Many times we are just like the protagonist in the movie who is trapped in his own dream or illusion.