Hi Mr Far From Right--a couple of responses to your questions.
First--My husband has been reading the thread and I've also been talking with him about my feelings as I process them. We've shared the forum with his GF, but not sure if she's been on here or read anything yet.
Agreed that it makes sense for she and I to spend some time together alone, which is something we're planning to do. We've had drinks together a few times, but I think we need some more intense "bonding time" to get to know one another better as people. Although we're open to the possibility of this being a triad, in reality it's still definitely a vee--she and my husband have the much stronger bond.
I also wholeheartedly agree that we need to work on the trust issues AND that my husband is maturing in this. It's been a process for both of us, breaking out of old ways of doing things and old mindsets.
Probably what has been most valuable to me in this thread is receiving validation from people about the impact that the cheating has had on my thinking. You've all really helped me separate out those aspects of my feelings that are related to needing to rebuild trust and those that are more about my own insecurities. I think that if we can build the trust, moving at a pace that indicates they are willing to work with me on the trust, I can move to a place where I'm comfortable allowing the relationships to evolve in the ways that they need to, including having it be a vee if that's what they want.