Thanks, Crisare. Lady Macbeth and I have been thinking the same thing, and with her history, she's been afraid of the possibility as well. She's trying to be cautious about inaccurately interpreting his actions, but at this point I really don't think she is.
During our talk to figure out what we were going to do about salvaging both relationships, I found myself getting sucked into his control. Later on, when we were moving into the negotiation phase, he had to leave to go and pick up his other girlfriend (who was going to be joining us). As soon as he left, it was like a veil was lifted, and I realized what had been going on. I was angry at myself for both being fooled, and for giving up everything that I had been so adamant about before we started. When he came back, I could tell he was shocked and confused, and felt like he was suddenly talking to a different person, since I dropped back to my stance of not wanting to just give up all of my control in my relationship. We ended up with no agreement on what we were going to be doing, which was fine by me. I have no intention of just letting him control my actions and feelings.
In his long diatribe at the beginning, he listed a bunch of issues, some valid, most not. He basically blames her for ALL of the problems in their relationship, admits no fault or any contribution to it, said that she could obviously not work on two relationships at once, and said that he didn't care about my feelings. It basically reaffirmed that he has completely bankrupted himself to me, both trust-wise, and as being worthy of my respect.
I'm torn, because I think she needs to leave him. Not for me, although she would be with me, but for herself. Fortunately, she sees what's going on. I'm doing everything I can to keep her spirits up, and keep her focused. She's been so confused by him, since he seems to have changed into a completely different person since we started dating. I keep telling her that he hasn't changed, she just hasn't had an opportunity to see the real him before.
Thanks, everyone, for their kind words and support. I'll post updates as it progresses. Cleaning out my office now, to make a guest room . . .