The secretion and maintenance of milk during lactation are regulated by neurohormonal pathway. During pregnancy, prolactin secreted by the anterior pituitary gland is inhibited by a large number of estrogen and progesterone secreted by placenta and ovary. After delivery, prolactin is released rapidly due to the sudden drop of progesterone content. Under the strong action of prolactin, breast tissue causes the secretion of milk. Since then, because the blood always contains a certain level of prolactin, the lactation activity has been maintained.
Guiding opinions:
Therefore, I suggest you drink less of your wife's milk. This is to change your wife's life, which is hard to be ethical. Besides, it will be gone after a while.