Sex and the City 2's storyline didn't get me hooked. The movie was fast forwarded at some points but the ending made up for it.
Black diamond to describe Carrie Bradshaw because she's not like the others.
Mr. Big bought her a diamond ring because he knew and he understood that she needed to have a "little" reminder everyday of her vow to him and their marriage.
Of keeping Carrie's house so somebody can have his / her personal space away from a relationship.
When you have been in a relationship as long as me, you can understand why these are steps to strengthen the relationship, and I foresee, with a marriage. Very, very sweet. Not signs of trouble, but substantiating actions and commitment to make a relationship work even better.