And there is a sense in which why anyone marries anyone is an unanswerable question. sometime it's obvious to those involved but not to others; sometimes others think they can see why. sometimes not. And sometimes those involved, or one of them, starts asking why they are where they are and isn't sure of the answer.
Even now it's quite possible to slide into marriage because it's what's expected of you - among my acquaintances there is a girl who wanted children but seemed to have no prospects of marriage. However, a suitable candidate was found and they married, I think a lot because both mothers, who knew each other, wanted it. The group to which they all belong were approving and the social endorsement made everyone happy at the time. I don't think either member of the couple was in love. Or is now. But they get along, most of the time, and they have a little girl, who seems to be a major link.
That's an aspect of Ennis and Alma in their early years, IMO. That he loved another man, even if he realized it before marrying Alma, was just beyond Ennis's ability to comprehend, much less deal with, while marrying her was what was expected and would be approved. In many ways love is disruptive, demanding and difficult; for Ennis loving Jack was just too much to cope with, other than "way the hell out in the middle of nowhere".
