Can I Listen to My Husband's
Yes, if it is on the same line that you also use. Even in this instance, you can only listen but not record your spouse's voice. States have various eavesdropping laws. But as a rule you cannot record someone's voice, even if it is your spouse without their consent. Both Federal and State laws prohibit such an action. Nonetheless, if you have a shared phone such as landline with two telephone sets, there is no law to prevent you from listening in on the conversation.