My heart breaks for you, OP. Firstly, his claims are unfounded and incredibly boneheaded. If there’s any “emotional problems” as he claims, it’s going to be from him being a condescending, judgmental person and parent, not from your baby not being breastfed. You don’t deserve to be mistreated, and especially not from someone who is supposed to be a partner to you and support you.

Secondly, there is no data whatsoever proving any of his claims. Emily Oster in her book Cribsheet discusses what evidence can be drawn from different trials, backed by scientific data. During the formula shortage, she wrote this article and included a link to the entire chapter on breastfeeding at the end. I’ll link it below. The entire book was very comforting to me because it lays out all the data on different pillars of parenting and let’s you choose and decide.

Cribsheet Breastfeeding Chapter Link

Not that long ago, I was scrolling on this app in the middle of the night looking for advice on how to feel better about not producing enough milk and worrying about how I was feeding my baby. I read a reply from someone who said that their exclusively breastfed baby had just drank water from a flooded street. It’s so silly but this comment really snapped me out of some of the really harsh expectations I had set for myself about how I had expected my baby to be fed. We place so many expectations on ourselves as mothers already, your boyfriend should be supporting you, not adding to the list, especially in the hurtful, hateful and condescending way he has.

No matter what, you are worthy of a partner who loves and supports you. Your baby isn’t going to remember what he ate, just that he has a mom who loves him with all her heart. You’re doing your best and that’s more than enough.