Two people who love each other are separated, and a phone call shows how much it hurts. He says he misses her, and she answers that she misses him too, though the poem tells us he has no idea how badly her heart is breaking. She wants to hold him and ease the pain of their time apart, which, as the poem says, is "through no fault of their own."
The moment that matters most comes when he apologizes. His silence, then the break in his voice, shows he is crying and trying to hide it. He feels ashamed of his tears. She sees them differently: to her, tears are strength, not weakness, and they come "from the heart."
The mood is tender and bittersweet, sad about the distance but warm with devotion. The poem ends quietly with her love growing stronger because he let himself be vulnerable.