Describe Catherine's thoughts and feelings on Heathcliff and Isabella's relationship in Wuthering Heights.

Catherine and Heathcliff had often made fun of the Lintons
when they were younger. This is what they are doing when Catherine is bitten by their
dog and must stay and recuperate at Thrushcross Grange. At this time, she meets Edgar
Linton and he falls in love with her. They eventually marry. Heathcliff returns and
finds Catherine married to Edgar. Edgar's sister Isabella becomes infatuated with
Heathcliff because he is grown up, handsome and rich. Heathcliff plans to take advantage
of this, marry Isabella, get her inheritance and also get back at Catherine. Catherine
tells Heathcliff that he could not possibly marry a Linton, which is strange because she
has done the same thing. Catherine knows that Heathcliff does not really love Isabella.
Plus, she wants Heathcliff for herself, even though she is married to Edgar. She has
also become fond of Isabella who is now her sister-in-law and she knows that Isabella is
a flighty woman with not much sense, so she does not approve of the marriage for
Isabella or Heathcliff. It is partly from selfishness and partly from concern for
Isabella that Catherine does not approve of their marriage.