I was sharing Netflix with a friend. When they moved forward with price increases, pushed to stop password sharing, and were found to be looking at introducing ads, I told him I'm not helping pay anymore and it's up to him whether he wants to cancel. Idk or care whether he stuck around and decided it's worth paying more than double what he had been paying. But withholding your share of the cost might convince your family. If it's your account being shared, just cancel it and tell them to launch their own account.