Understanding the meaning of the ending

-*Spoiler*-

Julio and Tenoch are best friends and horn-dogs, obsessed in upping each one's sexual prowess, until they come across a woman, Luisa, who becomes the source for a sexual triangle between the two boys and her.

At first I assumed the competition came between the two boys for her. When Julio finds Tenoch in bed with Luisa, he's sad and briefly isolates himself. Then when Luisa also has sex with Julio which leads into the boys fighting, Luisa screams about being tired of dealing with the sexual tension between Julio and Tenoch. I didn't take notice to what she said until they have a threesome which culminates in Julio and Tenoch passionately kissing. The kiss ends up being the barrier which changes the friendship. The boys distance themselves, never to share the same closeness they once had.

My question is: Were Julio and Tenoch unconsciously in love with one another and were completely in denial about their feelings by over-emphasizing their masculinity? Or were they in fact straight and the kiss (assuming it didn't go further as we don't know what happened next) overstepped boundaries they hesitated in breaking? Luisa appeared to be aware of it and she might have purposefully made it possible by engaging the boys into a menage.