Usually a couple shares an auto policy. If one spouse hits another with one of the cars on the policy, injuries would be paid out of personal injury protection. Bodily injury would most likely not apply to avoid a couple intentionally causing an accident to profit from the loss. Lost wages, medical bills and essential services are about all an injured spouse may claim after an accident caused by the other. Damage to property is covered if one or both cars have physical damage coverage. A deductible would apply to both cars. If one or both of the cars have liability only, then the couple will be responsible for paying for the damage out of pocket.
It would be additionally difficult for the couple who collide if each spouse has his or her own policy and with different insurance companies. The at-fault spouse's insurance company will discover the other injured or damaged party is related by marriage. Most auto insurance contracts call for all eligible autos in the same household to be covered by the same company to avoid conflicts in settling claims. An insurer can deny a claim when it is discovered there are multiple companies represented in the same house. It's a good idea to keep all cars and drivers on the same policy living in the same household.