I bet it"s hard and scarcy for the daughter too
When we decicded to be Ploy and our Wife moved in with us, we sat down and talk with our 13yoa daughter. She expressed fears about being shunned by others and her status in the family. within 6 months it was very different. She had another mom to get clothes from and do all things young ladies like to do.
Our then 9yoa, boy have cared less. He liked having another mom to do all the mom things do for young boys.
Just being open and even getting some family counsoling would help I bet.