Approaching the short story in its finalized form (with the italicized prologue in place), it would appear that Ennis never moved on emotionally, and almost certainly never entered into a relationship with another man. There are clues that Ennis has aged significantly in the prologue, and that many years have passed since Jack's death, and yet he is clearly alone (and subject to his daughter and son-in-law's hopeful kindness) and emotionally fixated on Jack, who now lives on only in his (grotesquely sad) dreams. I do think that Ennis by this point has owned up to his love for Jack ("Jack, I swear--"), but there is no clear indication that Ennis has reconciled himself to any idea that he is homosexual.
The film's ending has a more redemptive feeling than the story. We not only see evidence that Ennis finally realizes what Jack and he shared together, but also that Ennis has learned valuable lessons from his experience with Jack and is beginning to incorporate those lessons into his life. I have never felt that even movie-Ennis was likely to meet and cultivate another man in a romantic or sexual way, but I do have a strong sense that he has at last admitted his own queerness to himself, and recognizes beauty and strength in it, insofar as it describes his powerful and lasting feelings for Jack.