“If you don’t keep the Commandments, Bud,” you never converted in the first place. If you have been born again - made a new creation by the power of God - do you think you can uncreate yourself?
A changed life is the result of salvation, not the procedure by which we earn it.
You can surely "opt out" by committing deadly sin..there is no forcing by God to stay in this relationship. And that is what it is, a relationship with God.