First, if she'd gotten into the car and had an accident in which she was at fault, the injured party would be allowed to bring an action against her, the driver, because she is the party who has a duty of care to other road users. It would not be allowed to bring an action against him, the driver's husband, for not 'using reasonable force to stop his drunk partner from getting in the car and driving'.
Agreed. DOC is only to his partner in this instance.
Likewise, she, the driver, would not be allowed to bring an action against him for not restricting her from driving, either. Owing a duty of care to someone is about eliminating a foreseeable risk of harm to others by managing their own actions. It's not about depriving another of their ability to act.
Do not agree. There is both a negative duty and a positive duty when there is a duty of care. If your drunk partner was on a cliff top and in danger of failing off and you saw the danger and did not use reasonable force to get them away from danger and they subsequently fell off, you could be charged with a crime (not sure what negligently causing death is in QLD) and a have a civil claim against you from your partner's estate.
The only differences between the two examples is causation and reasonable foreseeability. Harder to prove the link in the driving situation but still possible.
BTW, I still agree with you that a magistrate in a AVO/DVO case is not likely to care too much why someone caused the bruises when their partner makes a claim of violence against you.