First of all, gigantic kudos for recognizing the significance of this timeframe.
In all likelihood, her emotions are about to take over. The mind movies get especially intense here, and we start to question R, question ourselves, question the WS as if it is all actually happening again.
I suggest being a rock of consistency for her. When she breaks down, hold her. When she gets angry and you start to feel defensive, remember that she's triggering and needs your compassion and reassurance.
If she's asked for them, romantic gestures would be good here too. There's a chance she'll lob them back, but it is a great idea to try and coat over her mind movies with things you can do for her to show her that she's the one you want to be with. Get flowers. Leave love notes.
One of the most humiliating things about being a BS is that we accepted that our relationship had changed - matured if you will, while the WS thought they needed something different and new. Treating her as if you were courting her might make her feel that tingle that she was kept so very far on the outside of this time last year.
Wrapping back around - being a rock for her is the most important thing. Tell her every day that you're not going anywhere. Ask her what she needs, and see past her anger and her pain as the demons pick at her from the inside.
Honestly, the fact that you're aware of this and asking us for help is very encouraging. You can do this!