Mary is first described as a physically attractive person with an emphasis on human desire and pleasure. The relationship progresses to the point where Mary is seen as a complete though flawed individual with personal characteristics that are admired. By the poem's end, however, Wordsworth has developed a profound appreciation of his wife's brilliance and wisdom. Wordsworth's description of his wife may demonstrate how an intimate relationship overtime.
We are presented with three depictions of women -- objects of beauty, flawed imperfect beings, and individuals with power and wisdom gained through suffering and endurance.
Consequently, Wordsworth is describing his wife, not as how she is in the present, but his perception of her at various points in their marriage.
This poem shows us that there is not a persistent definition of beauty or womanhood in this poem.