Let's start with what we know. She is married to Marco. She has an affair with Raju. She is beautiful and she is a dancer. Just from that a reader can start gleaning some extra characteristics of Rosie.
She is married yes, but it is not a happy marriage. Her husband, Marco, is gone a lot on archaeological studies. This allows Raju time and opportunity to woo Rosie. If she was in a happy marriage his attempts would have not made any difference. So she is either unhappy, a flirt, or just not committed to her wedding vows. This trait of falling hard in love and then "cooling" off seems to be a theme with Rosie. She does run away with Raju, but he doesn't treat her that well. Yet she stays with him. Battered wife syndrome? Of course she doesn't stick around after he gets thrown in jail, so again Rosie isn't that committed to the men in her life.
Rosie is more than just a good looking dancer. She must be a great dancer, since she is able to get a job as a dancer and earn a wealthy income. Interestingly though, she doesn't care too much about the money. Raju does. To me, this allows Rosie to be an "artist." She dances because she loves it and because she is good at it. She doesn't do it for the money; it's simply a part of who she is.