I'm interested to know how you and your wife are dealing with rebuilding trust in your relationship? I suspect that without it, it'll be very difficult to move forward with both of your loves.
You seem very focussed on how to keep both relationships and I wonder if that focus is a little off?
My experience has been that broken trust in relationships takes a very long time to repair - in my case it was a couple of years after a significant break in trust before I felt like I could trust that particular individual again. Much of that time was spent working on rebuilding the trust that had been lost.
For me, the broken trust was the issue and at that time, I would not have been open to dealing with rebuilding trust while also trying to deal with the situation that had caused the broken trust still carrying on.
I hope you and your wife and your gf are able to work things out so that all of you can feel secure and happy.