Dear Thomas - that was really pertinent information, there, based on historical models in the past. I hope I've got it right:
romantic friendships - sensual, but rarely sexual
romantic loves - usually leading to sex
This, of course, makes "Friendship, sex, and love..." as a topic, somewhat more complex, but if it's there, and IMO, it IS there, what you did was to add a critical dimension.
I would add, I really don't think this was just the 19th century. I have a very strong belief that men and women "bonded" with someone of the same gender, all the way back through the history of humanity, that it was non-sexual, and that, essentially, homophobia, where it may have always been around, has accelerated in modern times, terrorizing people and stealing from them any chance of fulfillment from friendship loves, whether romantic or not.
David and Jonathon, Henry 1V (?) and Thomas a Becket, Henry VIII and Thomas More, Mary Stuart and Arabella Stuart, Queen Anne and the Duchess of Marlboro are examples of the famous, but how many farmers and soldiers formed solid loves, which now would come under fire from homophobes as being gay, or from gays as needing to be "outted"? SOMETHING was there that was permitted and not condemned and which has been STOLEN from Western culture in modern times.
Well, you've mentioned Jack as moving from romantic friendship to romantic love, and I've used the term "sacred friendship" for Ennis' initial feelings.
I am thinking, they mean the same thing. And I do believe you are right, Jack went from one stage to the next fairly quickly. This undermines the hopes of those who want to see massive sexual attraction, repressed, outside Aguirre's trailer. But it does not undermine the general theory that both were awakening to same-gender leanings, so I hope no one gets miffed there.
Gosh, I wish I had seen that program.