Hello and welcome to Apple Support Communities, Khalil_AK,
If we understand your post correctly, you'd like to know what happens with your music library and playlists when you leave a family sharing group. That's a great question and we’d like to help.
When you leave a family share group with Apple Music your music library and playlists remain intact for a grace period. This allows you time to sign up for Apple Music on your own if you choose to do so. You won't be able to listen to the music until you have an active subscription but it doesn't take long to make this change.
In your situation, you and your wife can leave the family share you're currently in. You can then create a family share group of your own and subscribe to Apple Music. The articles below will help you do that:
Leave Family Sharing - Apple Support
Get an Apple Music family subscription - Apple Support
Let us know if you have other questions about this process.
Thanks for using the Apple Support Communities.