What is the theme of sonnet 130?

This sonnet has a passionate and mysterious theme ' the dark lady!' Although the main theme is love, the fuller discussion rests on the idea of 'loving as a friend.' Many people will be familiar with the saying 'but we can still be friends.' But is this true? Can a physical love ever exist in special friendships without platonic love,and vice versa? In a relationship of 'true minds' only, will both halves of the couple be truly and completely happy? A poetry example from more modern times springs to mind - W.B. Yeats was sick with love for Maud Gonne for most of his life, yet she could see no reason for his unhappiness in settling for a close friendship where he shared the friendship with others. In this sonnet, in the end the question is whether the steamy affair that follows has spoilt the chance for an everlasting 'purer' love for ever.Another theme is the true value of metaphors for love in poetry and whether they can actually come close to what love is actually like (a rose, a summer's day, a sickness in various poems.) In some poems, the metaphors cannot do justice to the beloved, but this sonnet 130 is more down-to-earth as the poet appears to actually realise that 'my idol has feet of clay' as another writer puts it. The subject,although loved,has imperfections that the poet can see.