[Blame her parents and their encouragement of damaging coping methods with bad emotions!]

It's... [Again, she wars with the urge to clam up and the desire to talk. She shouldn't talk about this, she just has to deal with it...! But no. Elsa's never been a very emotionally strong person, and eventually she crumbles.] I can't let her know, because if what you say is true about this "open relationship"... I can't let myself reciprocate. Because of my responsibilities.

[there she said it]