If they'd uttered the little three words, I'm pretty sure they would come over as being superfluous, redundant...that is how palpable their love was...it was best left unsaid, no need to say it. The lack of hearing it compounded the love, in my opinion.
Back in those early days, most guys simple don't say those three little words, not even to girl friends or wives. It just felt too deep. Even Jack, had to use euphemism one way or another, "I missed you so much I can hardly stand it" or "I redlined here all the way" or doing all the little things for twenty years.
Yeah, I think saying 'em words would be redundant, and superfluous. But d@#% it, I wish they did utter their love, openly and honestly. In many ways, the lack of the utterance was part of the hiding in the closet for Ennis. And the lack of it, always put doubts between them Jack never knew for sure what Ennis wanted, and Ennis never knew how deeply Jack loved him, until the two shirts in the closet. Yes, they knew there was something...no reins on this one, between them, but they didn't put a label on it, like tpe often said. And sometimes, having a label on things, helps to rein it in, and make it more real.