Treating fiance like mom

We are a couple who ve been together for a year and a half. We are living together and get a long pretty well. There is one unique thing about us. For more than a year we started to develop kind of parent-child relationship, usually with a lot of baby talking. We are calling ourselfs mum and baby alternately, so the future husband became a mother too for his baby future wife. We never considered that as an issue until now. We don't know if it could cause low libido issue for her.
She loves me deeply, feels safe and happy with me, but for a couple of months she didn't feel any physical desire for things like long kissing or sexual activities, She loves to cuddle and show a lot of affection. She gets turned off by thinking of any kinds of sexual activities with anyone. We still want to have a family with lots of children.