I have moved your question to this group because How Do I Love Thee? by Helen E. Waite is actually a biography of Elizabeth Barrett Browning rather than a poem, so I assumed that it was this famous sonnet that your question refered to.
This is the most famous poem of Elizabeth Barrett Browning, written as part of a sequence of love sonnets to Robert Browning, her husband. In this poem, however, the love that the speaker has for her beloved is fully realised, and highlights both the spiritual and earthly nature of this love. The love that the speaker has seems to occupy every part of every sphere of her life, both her soul and her earthly existence, the "quiet need" of her humdrum life. The world of the speaker is shown to alternate between happiness and unhappiness and day and night, but the love she has penetrates all of these emotions and times. It is important to note that in this pageant to the power of love, the ending of the poem recognises the way in which death will impact the love she and her lover share:
I love thee with the breath,
Smiles, tears, of all my life! --- and, if God choose,
I shall but love thee better after death.
Note how life and death are juxtaposed in this ending to highlight the way in which at the ending of this poem, just as in the ending of her life, what is temporary and what is eternal unite as, with the aid of God, the lovers move from their own earthly enjoyment of their love to what the speaker hopes will be a more refined and intense love "after death," where the speaker hopes to "love thee better."
Thus this poem describes a love that envelops the temporary and the eternal as love and the feelings it engenders are explored from a female perspective.