My husband hides our daughter from his family

I had a 13 Years old daughter before meeting and marrying my husband. He loves her dearly but he hides her from his family. We have another girl together and he shows her off to the world. He upload only pictures of our second daughter, his family only knows about our second daughter. He said that it is against their belief to marry a woman who has a child for another man. We travel to see his family in Africa Nigeria and always have to leave our first daughter behind.

This time around he wants us to travel again, but I have told him that I want our first daughter to come with us. He is making a big deal out of this and saying it will bring shame to his family. I really want to know what sort of belief this is