Your Spouse will be available once you have completed the The Honey-do List Chain. You can do everything with your Spouse you also can do with your main character except visiting your neighbors. (You wouldn't want you spouse to "hang out" with the neighbors too often...)
When your spouse takes an action, it use up energy from the same pool as when you take an action. Weapons are shared between you and your spouse. You can choose for your spouse to be the same sex as yourself, or the opposite sex.