Each of the times we see Jack being unfaithful, like in Mexico as has been said before, he looks like he is just going throught the motions, there is no joy in his face. When Randall is sitting on the bench with him outside the dance, watch Jack's face....it's like OK then lets....no real passion.
Compare this to the reunion scene, unadulterated joy. It makes my heart soar for them. :D
When they meet down by the river and Jack is waiting, watch first his face as Ennis pulls up and then Ennis's face as he gets out the truck and looks at Jack. These boys are in love.
The Acting skills of Jake and Heath here is wonderful. It is a story but here those joyous expressions make me totally and utterly believe that these two men are in love. I forget at these two wonderous parts of this story that I am watching a movie.
The thing with Jack, he wants the love and the sex...he beleives he can get both from Ennis. I know that he knows Ennis loves him, but somehow it isn't enough. Totally wonderful, absolutely tragic, classically heartbreaking. :'(
Tom