The tone of the poem is deeply romantic. The the poet emphasizes the various ways in which she loves her husband, associating with her love the virtue of “Grace” and the purity of those people who shun praise: “I love thee purely, as they turn from Praise.” Modern love songs usually are humorous and sometimes passionate but more lighthearted.
The rhythm created by the stress on syllables and the rhyme scheme in the sonnet give it a musical quality, while modern-day songs usually use music to provide the rhythm (although some also use rhyme and create a rhythm with the word choices).