Obsessing is very normal in the beginning. Rehashing conversations, events, images, over and over and over is our mind's way of processing the trauma and shock and eventually gaining clarity.
Wondering if you are 'doing the right things'? If this is regarding WS, well, you don't really. Since they are supreme liars and deceivers, you don't really know what's in their thoughts or if they are just giving you lip-service to pacify you.
That's why the 180 is a focus on YOU, not them. It cuts off their control over you and ability to manipulate you. It's not a game, it's a life saving technique for yourself. You cannot be drawn into arguments (so they can have false vindication to run off to see op). You cannot be sucked into THEIR drama. You cannot be drained of energy by interacting with WS.
You cannot control what they are going to do, you can only control your reactions to them and by doing 180 you shut them out and shut them down.