
Lol mom of 3 here, uhhh none of that is true. Just don't let hubby suck on your breasts because of contagious diseases baby may catch. Nothing about nutrients. OBGYN'S actually tell mom that have a clogged duct to have hubby suck to unclog it after a hot shower. Breast milk is packed of vitamins and nutrients on a cellular level. It won't stop until you and baby are ready to stop nursing. Thank you for my Ted talk.

hallo biomed student here!
so my og comment had a point to it actually, specifically in saliva (like amylase and lipase) can start breaking down carbohydrates and fats. This doesn’t instantly ruin the milk, but over time it could change its taste or texture. also bacteria from the mouth of an adult can seed the milk, which is one reason why stored milk that’s been drunk from directly should not be saved for later, so it spoils faster. there’s also the immune response angle, there’s some research suggesting that when an infant’s saliva mixes with milk, the mother’s body may detect pathogens and adjust immune factors in future milk. however yes, this is a long-term, signaling effect, not an immediate change in nutrient balance. so while a partner can help with unclogging ducts, just in general we shouldn’t let our partners drink from milk ducts in the long term!
random thing but when you’re breastfeeding you should actually never let your partner drink from your milk ducts as their saliva makes it so the vitamins/growth hormones you’re producing for your babies changes! the saliva from your babies makes you produce certain nutrients more than others to help them grow properly, so if a partner latches onto your ducts it can actually throw your body’s milk production all out of wack for your baby!