Jack was ever the optimist (well, perhaps until the very end
), so that sounds about right to me, too. I really hear the "I'm sorry" as just meaning for the night before - like "I'm sorry if I scared you or put you in a bad position (so to speak) last night - I just wanted you so much that I couldn't wait any longer." And it seems that Ennis nods just the tiniest bit right when he says, "I'm sorry" as if, in his own way, to say, "It's all right. I wanted you, too. Obviously."