Answer
In the Name of Allah, Most Gracious, Most Merciful.
All praise and thanks are due to Allah, and peace and blessings be upon His Messenger.
In this fatwa:
The drinking of your wife’s milk does not invalidate your marriage. The husband and wife are still considered as a legal couple in the eyes of the Shari`ah.
Responding to the question, the Islamic Religious Council of Singapore, states the following:
Every Muslim is strongly recommended to follow the Prophetic guidance in enjoying the intimate relationship with his wife. The female breast milk is intended for babies, and hence it should be left for them. It is not for adult consumption.
With this in mind, we can say that the husband is allowed to suck on it gently, but he is not allowed to draw the milk in. According to the opinion of some scholars, if he were to do so, it could endanger the marriage relationship—if suckling is done five times.
The drinking of your wife’s milk does not invalidate your marriage. The husband and wife are still considered as a legal couple in the eyes of the Shari`ah. This is because only a child who has suckled a woman’s milk fully, more than five times, is considered as the woman’s suckled child.
Hence, your children are considered as both your legitimate children and you can continue your normal relationship as husband and wife.
For more, see these fatwas:
Can I Use Obscene Words During Intimate Relations?
Intimate Relations During Wife’s Menses
Are Intimate Relationships Allowed in Ramadan?
Are Sexual Relations Between Non-Fasting Spouses Allowed?
Intimacy during Period in Islam
Is Cybersex On Skype Permissible Between Married Muslim Couples?
Almighty Allah knows best.