Watching someone you love stand alone, the speaker realizes what they never said. The poem is a quiet confession of regret. The speaker lists small, specific things they adored: a dimple, the eyes, a laugh, a smile, a carefree way of being. These details feel affectionate and a little shy, as if the speaker has been memorizing them for a long time.
The sting comes at the end. The word "aisle" suggests the person they love is about to marry someone else, and the speaker imagines that speaking up might have changed things: "it would be me." The broken lines and the awkward stop-and-start rhythm, like "Your laugh, / Smile," make it sound like someone fumbling for words, which is exactly what they failed to do before. The mood is wistful and bittersweet, heavy with "what if." There's no anger here, only the ache of a missed chance and the sad knowledge that the words come too late.