Why does Blanche want to find an escape plan for Stella? How would Blanche benefit from this plan?

Scene please?

Scene 4 or 5

In Scene Five, Blanche attempts to make an escape plan for Stella based upon her walking out on Stanley the night before. Blanche finds Stanley's behavior barbaric, whereas, Stella finds it exciting. Blanche finds it impossible to understand that Stella and Stanley thrive on their arguments and enjoy making up. Thus, Blanche makes the effort to convince her sister to leave, and even goes so far as to call and old boyfriend, a rich boyfriend, to fund their escape. Over the course of the scene, we come to realize that Blanche's desire to leave and her attempted request for money is self-serving.... not compassionate.

What does stella reveal to Blanche about her relationship with Stanley? What is it that draws them together?