It comes down to this....Wife called 911, police are dispatched to a domestic disturbance. New domestic violence laws require LEOs to do a thorough investigation to determine if a domestic violence crime has been commited. This is for the protection of the victim(s). Husband resists investigation. Pushing an officer, or anyone for that matter, constitutes an assault. Husband was subdued using less than lethal means. Officers are allowed to to use one level of force above the level being used against them.
If the wife wasn’t physically harmed, nor in danger of being physically harmed, she should not have called 911 as there was no real emergency. If you call 911, police and/or medical services are going to show up and investigate.