Urgh, I had a whole wonderful post typed out and accidentally closed the browser. Ok, here goes again.
I understand the "want" to contact the OBS. You two share a unique, painful experience that only the two of you can understand. No one else on earth was betrayed by your wife and her husband besides you two. This unique pain can form a "victim bond" if you will. Sort of like siblings who are raised in an abusive home, they will bond over those abuses often because no one else understands what they've been through other than their sibling.
I would still not recommend contacting her though. She might be in a different place in her healing and either one of you might end up feeding off of the other one. If she is in the rage stage, she might help you jump right into it as well and vice versa.
I understand how, as a compassionate human being, you want to check and make sure she's doing ok. But what if she's not? It would probably kill you to know that she's miserable, tried committing suicide, given up her kids for adoption, moved to Zimbabwe, shaved her head, etc. etc. etc. What would you do then? Contact her weekly and try to become her counselor? You can't fix her, you can't even help her fix herself, she has got to do this on her own. I know it feels counter intuitive to just leave her be as a caring human being, but in this situation I think it's best to do just that.