He wants George to "breed" with the girl. In Vol I, Ch Xi, George pleads with the "kind" Mr. Wilson to understand and help him:

"...Then sir, I found my wife; you've seen her, -- you know how beautiful she is. When I found she loved me, I married her, I scarcely could believe I was alive, I was so happy; and, sir, she is as good as she is beautiful. But now what? Why, now comes my master, takes me right away from my work, and my friends, and all I like...and last of all, he comes between me and my wife, and says I shall give her up and live with another woman.