Ok, this is a serious reposne to this.
Since I am not sure of the sex (or sexual leaning) of everyone who has responded thus far, please forgive the generlization.
We are talking about 1983. I am gay and in 1983, there was no way I could have been in any kind of openly gay relationship (and I was out then), and I lived in Boston. Gay men and women and those with transgender issues, were tolerated, but still hidden, and still considered socially deviant. "Will and Grace" was a long way off.
It is a tough thing not to impose out modern day sensibilites on the situation back in 1983, either for me or for the fictional Ennis and Jack in their rural setting, which no doubt was far more oppresive than where I was.
That being said, Ennis would never had a moment to breathe easy let alone come to terms with his sexuality. He could barely acknowledge the love he had for Jack, until forced to by Jack's death.
While the love they felt was certainly enough to sustain a relationship, emotional, and societal pressures would have surely driven them apart eventually. Neither one had enough emotional stability to forge ahead despite the oppostino they would face. I had seen that happen to many of my friedns back then. It happened to me.
It's just a fact of life 25 or so years ago, that gay relationships were not supported or condoned, and they were always outed eventually.