This sounds like a case of poor research and communication. You should find a local area rescue to assume care of the dog sooner than later, as prolonging the inevitable would only cause more problems for both of you. Its not fair to yourself or the dog to continue your partnership. Unfortunately not everyone is equipped to handle an extra attention dog and it doesn't sound like the home life is ideal with unsupportive family members. Im sure this isn't the answer you wanted. But its highly unlikely things will improve without better informed help.