When she comes back to the hotel room, her husband is still reading. She tells him that she does not know why she wanted that cat so much, but we know it: She feels the need for something to care for, to be responsible for, that makes her grow up, for example having a baby. George does not need all that anymore, because he already is grown up, which is shown by his serious behaviour and that he treats his wife like a child. And now we understand why why they are having problems with their marriage - because they are on different levels: He already is a man, she is still a girl. They cannot find a mutual base for their relationship and that makes her bored by him and him annoyed by her.
But George does not understand the problem of his wife and therefore of their relationship, because when she talks about letting her hair grow to make her become more female, he just tells her with disinterest that he likes it the way it is.