Stella uses sexual advances to control Stanley. She wants to appear as a woman with a strong character and the only way to achieve this is to use sex as a threat factor against Stanley. Stanley uses sexual advances through physical force, to take command and assume the role of the alpha male. Stanley wants to be in control of everything and uses sexual advances to rape and break Blanche, and essentially take control of her destiny: to be sent to a mental institution. What this says about Stella and Stanley's relationship is that their marriage is unhealthy. It's just based on sex. When Stanley beats Stella, the only way they can truly get back together is through sex. It is a physical based relationship