Catherine and Linton's relationship

I'm very unsure of what to make of Catherine and Linton's union. They obviously aren't madly in love with each other. Catherine had cultivated an interest in him and used to secretly correspond with him but does she really love him? She reasons with Heathcliff that there's nothing he can do to make Catherine and Linton unhappy. She insists that she has something he no longer has: love. However, I think she really married Linton because she felt bad for him and because he was being forced to court her by his cruel father, Heathcliff. She knew that if she rejected him, Linton would face severe punishment from Heathcliff. Perhaps they grew to love each other. Here is an image of Linton.