Sonnet 42
That thou hast her it is not all my griefe,
And yet it may be said I lov'd her deerely,
That she hath thee is of my wayling cheefe,
A losse in love that touches me more neerely.
Loving offendors, thus I will excuse yee,
Thou doost love her, because thou knowst I love her,
And for my sake even so doth she abuse me,
Suffring my friend for my sake to approove her.
If I loose thee, my losse is my loves gaine,
And loosing her, my friend hath found that losse,
Both finde each other, and I loose both twaine,
And both for my sake lay on me this crosse.
But here's the joy, my friend and I are one,
Sweete flattery, then she loves but me alone.
Commentary
Address to an unfaithful young man
Changes to the original text: end of line 12, full stop supplied for comma.
There is evidently now a three way relationship: the poet, the young man and a woman. The woman was clearly in a relationship with the poet before proceeding to seduce the young man.
In the first quatrain, the poet sets out the situation: he loved the woman, but that is not his main grief. His main grief is that he has lost his friend to the woman.
In the second quatrain, the poet tries to rationalise the situation by pretending that his friend loves the woman because he (the poet) loves the woman, and the woman loves the friend because he (the poet) loves his friend.
In the third quatrain, the poet complicates the matter further with a complex of cross-relationships.
In the final couplet, the sophistry is completed by his claiming that in seducing his friend, the woman actually loves him (the poet) as he and his friend are one.