She is supposed to spend at least one night at our house, and that is still happening. I don't know how to face her. My BW has thankfully decided not to tell her parents in case she decides to attempt reconciliation. I am going to be expected to spend time with everyone probably have dinner with everyone, etc.
I am looking for advice on how to handle this being that it will only have been a week since I confessed everything to my BW. It is just so fresh and I don't know how to face my SIL.
Because she knows whats going on, I think this is something you need to face head on. Have a conversation with her when she gets there, admit what you did and talk about what you are doing to fix it. Apologize for hurting her sister and her by extension. Ask for her support for her sister. Make it about your BW, and not you.
The people you do your life with shape the life you live
I believe wifehad5 gave great advice. My WS confronted the issue head on with my sister. He couldn't do that face to face because we are far away; instead, he called her and spoke to her at length about everything. He took the time to apologize to her for hurting her and our family with his actions, as well as hurting me. He asked for her to give him time to make amends. He did not ask for forgiveness, only for her to keep an open heart.
I know that was a really hard phone call for him to make, but it went a long way to healing their relationship. It will never be quite the same, but it is again friendly, loving and strong.
It will be really tough, but will show your BW and your SIL that you are willing to face the consequences of your actions in order to reconcile. Good luck.
I say talk to her before she comes. Apologize, thank her for her support, and ask that the visit be about her visit...not private issues.
I have confidants and so does my husband, but none are invited to enter the conversation between us.