An instinct for me was to consider breasts to be sexual and when babies breastfeeding wasn't, there was something not lining up that I had to contemplate.
What I realized is breasts are sexual and that is okay. Babies breastfeeding is innocent and that is okay. Both can be there because sexuality can be pure of heart. Loving and innocent just like a suckling infant is truly innocent at its core.
The problem was that what we think of as sexual is not how sexuality is meant to be. We think (what I mean here is: our society perpetuates an attitude) of sex from an almost strictly lustful perspective where even when we don't acknowledge it, women and their bodies are play things; toys to be played with by their partner; something naughty. And so thinking about a child sucking from a breast feels unnatural and uncomfortable.
To be real, we have it all backwards with what is natural. Breasts were made to feed babies. Humans are the only animals that have breasts when they are not nursing a child, so I think it's safe to say that breasts are also for pleasure and connection with a partner; but how can those two things have a common ground? Nurturing, comforting, giving, loving.
It is sad that popular culture has made women and their bodies into sex toys. Breasts are twisted into disgusting sex toys and not seen as their true nurturing selves. Breasts are nurturing. Nurturing of love, husbands and babies. Not "sex toys", but a part of the human body.