I had no idea that this movie was an entry in Cannes, until I was looking for the above movie poster. I would say that his movie is part about masculinity and sexuality as it is about relationships and life-partner relationships.
In short, the movie begins with Andrew showing up at Ben's house at an ungodly hour from Mexico City where he has been a goatherd or something like that. They have this weird homosocial thing going on that apparently shadows as one-upmanship. Andrew has Ben come to this lesbian like sex commune house party where they get him drunk and stoned. They begin discussing how they will be making erotic art films for the local amateur porn festival and Andrew is trying to figure out his own creation for the fest. Ben suddenly suggests that he and Andrew have sex on camera saying its not gay, it's beyond gay. It's not porn, it's an art project. The homosociality turns much more openly aggressive until eventually Ben's wife finds out about the plan --- oh did I forget to mention her?
The last fifteen minutes of the movie are highly conflicted and painful to watch -- in a good way -- when the two main actors make it to the hotel room where the will film their submission to the festival. If you've ever had unrequited love, entanglements with a gaytripper, etc., I wouldn't miss this film -- even if the beginning is a little slow and the cinematography awkward.