What does the knight mean when he says, “Take all my wealth and let my body go”?

The Wife of Bath tells a story of a knight who, having raped a woman, is sentenced to death. However, King Arthur, at the request of his wife, decides to be lenient. He suspends the death sentence and allows his wife to set the knight a challenge. The knight, she says, has one year to discover what it is that women desire the most. At the end of the year, if he fails, he will be executed. Just about a year later, still desperate to find an answer and the date of his execution rapidly approaching, the knight meets an old hag, who, to his great relief, gives him the answer. However, in return she makes the knight promise that he will marry her and, as part of the marriage, take her to bed.
The knight presents the answer to the king and queen, and it is accepted, but, when confronted by the old hag and asked to fulfill his part of the deal, the knight exclaims,

But for God's love pray make a new request. Take all my wealth and let my body go.

He is so disgusted with the hag's body that he begs her to take all of his wealth in lieu of insisting on marrying him. He knows (and is repulsed by the idea) that as part of the marriage deal, he will have to take her to bed and have sex with her, allowing her to "take" his body as she pleases.