cat on a hot tin roof

I never read cat on a hot tin roof just the title was pretty ambiguous to me. After reading it was pretty ambiguous how the cat is a metaphor for Maggie. In what way is she a cat? How a cat can jump off a roof and land on its feet and pick herself right up or having nine lives and she can survive any life she lives. The relationship between Maggie and Brick its pretty ambiguous on how why Brick wouldnt sleep with Maggie? It's obvious why Maggie married Brick for money(this seem to me like a streotype a women only marries men with money), its unclear why Brick is still with her if he doesn't love her. Also the relationship on Brick and Skipper, Were they lovers or just good friends? It is hinted that they were probably more than just friends, but it's not clear.
Also the relationship between Big Mama and Big Daddy. Big Daddy is 65 years old and he seems pretty miserable with Big Mama. But why until now is he admitting to it? The ambiguity between the characters why they remain in relationships that they are not happy with is unknown.