The difference is...?
What is the difference between つま and かない ? And also the difference between おっと and しゅじん?

Question

Answer

つまand おっと are formal. They are names as a spouse. They mean "wife" and "husband".
かない and しゅじん are informal/casual. They mean "my wife" and "my husband".
おくさん and ごしゅじん are informal/casual. They mean "your/his wife" and "your/her husband".