That thou hast her it is not all my grief,
And yet it may be said I loved her dearly;
That she hath thee is of my wailing chief,
A loss in love that touches me more nearly.
Loving offenders thus I will excuse ye:
Thou dost love her, because thou know’st I love her;
And for my sake even so doth she abuse me,
Suffering my friend for my sake to approve her.
If I lose thee, my loss is my love’s gain,
And losing her, my friend hath found that loss;
Both find each other, and I lose both twain,
And both for my sake lay on me this cross:
But here’s the joy; my friend and I are one;
Sweet flattery! then she loves but me alone.
In plain English
The speaker isn't most hurt that his lover is with the young man—though he did love her. What cuts deepest is that the young man has her. He's lost something in love that strikes closer to home.
The speaker tries to make peace with both of them. The young man loves her because he knows the speaker loves her. She accepts the young man partly for the speaker's sake. So they're both, in a twisted way, loving *through* him.
If the speaker loses the young man, that's actually a gain for his lover (she gets him). If he loses her, the young man gets her. He loses both of them, and both justify it by claiming to act for his sake. But the speaker finds one strange comfort: he and his friend are so close they're almost one person—so really, when she loves the friend, she's still loving only him.
