How do I opt out of family sharing or just quit family sharing

I just wanted to share my music and videos with serveral of my devices, as well as my friends devices that walk into my wifi area and I give permission (via network password) to stream content. Family sharing has nothing to do with that and now billing is always asking for a credit card. Well I don't have one, so my friend decides to be a nice guy and puts in his info and that worked for a while but now after updating to the latest OS, I can't change it back and its asking for a different payment because my friends has declined. So maybe its because family sharing is turned on so I dont want a payment resource of any type linked to my apple ID account because it restricts the whole account at times. I just want to be worry free and avoid any unnessesary charges to the only account of any type, I still have in good standing. Please help because all the apps I had on my phone were free and I cant stand not having them. "I Need My Games!"

Thank you for your time and attention to this most desperate matter.

Bottom line, How do I quit family sharing, opt out of family program, etc.