What conflict occurs between Heathcliff and Catherine in Chapter 15? How is the conflict resolved?

Heathcliff asks Catherine why she betrayed them by marrying Edgar. It is all her fault, he tells her--nothing could tear them apart, except her own actions. When she asks him for forgiveness, he says: "Kiss me again, but don't let me see your eyes! I forgive what you have done to me. I love my murderer--but yours! How can I?"