In loving thee thou know’st I am forsworn,
But thou art twice forsworn, to me love swearing;
In act thy bed-vow broke, and new faith torn,
In vowing new hate after new love bearing:
But why of two oaths’ breach do I accuse thee,
When I break twenty? I am perjur’d most;
For all my vows are oaths but to misuse thee,
And all my honest faith in thee is lost:
For I have sworn deep oaths of thy deep kindness,
Oaths of thy love, thy truth, thy constancy;
And, to enlighten thee, gave eyes to blindness,
Or made them swear against the thing they see;
For I have sworn thee fair; more perjured I,
To swear against the truth so foul a lie.
In plain English
You know that loving you has made me break my vows—but you've broken yours twice over, swearing love to me while you were already married and now swearing hatred after taking new lovers. Yet why do I accuse you of breaking two oaths when I've broken twenty? I'm the real perjurer here.
Every vow I've made to you is just a lie I use to manipulate you. I've sworn false oaths about your kindness, your love, your faithfulness—and I've actually blinded myself (or made my own eyes lie) so I couldn't see the truth. Most shamefully, I've sworn you were beautiful when you're not, which makes me a worse liar than anyone.
The speaker turns the tables: yes, the dark lady has been unfaithful, but his crime is worse because he's made himself complicit in delusion. He's sworn false oaths not out of circumstance but out of deliberate self-deception and manipulation. His final admission—that he's lied about her beauty—frames the whole affair as built on his willing corruption.
