Doesn't Shilpa know about AR history?

On Ridhima's birthday, Armaan said a lot of things including "Women should handle their husbands instead of their Ex" so:

how come Shilpa doesnt think about what happened between Armaan and Ridhima?
How come Shilpa doesnt ask any one why they are not together?
How come this thought never occurs in Shilpa's mind that AR were together and Rid is her sister and Armaan the guy she loves?

Or does she really not know about them?