Did you notice no wedding ring..why?
I actually reran that section of the movie and confirmed. Joanna was not wearing any rings on her left hand.
Now, since nothing does unnoticed in movie making I wonder why they made that choice. If it's a feminism thing...well, with a husband who works, two kids at home in the suburbs that might be a little late for that. Besides in the mid 70s and married women wore their engagement and weddings-even when they went shopping.
(I did not notice if the robot/clone had a ring on in the super market scene.)