What is the probable relationship between the speakers?

W: Love, my stomach aches.
M: Mine too, honey.
W: I think it was the fish or the meat we ate in the restaurant.
M: It might have been.
W: Or the soup.
M: No, it couldn’ t have been the soup because I didn’ t have any. Little Jimmy had some and he’ s all right.
W: Of course, we sat in the sun for a long time, but I suppose it couldn’t have been the sun.
M: That’ s true. Now what else did we both eat? Only those lovely apples I bought at the market. It couldn’ t have been them. We’ re used to eating apples and you washed them.
W: No, I didn’t. I thought you had.
M: Oh, Jenny, I didn’t wash them. I’ ve thought you did. It must have been the apples then. Oh, I feel worse now. Let’ s go see a doctor.