The question Paul seems to be preparing us for is, "Whose lover are you?" If we're joined with God, we'll bear fruit for Him though that union (what Jesus called "abiding" in John 15) It's possible for us however to have another lover. Paul is preparing us to think about a contrasting kind of fruit and how it is produced.
As death opens up the possibility to the married woman to have a new relationship in life, so the death of Christ makes a new relationship possible for the believer - though our own death to sin.
It doesn't mean that the Law is erased or that it is bad, however, because Paul later says in verse 12 that the Law is "holy, righteous, and good."
