Normal or fetish

Okay so I was curious on why my baby’s father loves sucking/licking/nibbling on my boobs (no I dont produce milk) he’s been doing it way before we had a baby together. I could just pop a titty out and he’ll go for it. Do y’all think that’s normal or does he have some kind of fetish.

Just FYI I’m not complaining just curious 💁🏻‍♀️