Sal, you sound like a bit of a control freak as well. (Takes one to know one- I'm a control freak too.)
Okay, I'm a person who married the wrong guy, divorced him, and went back to the love of my life, so I have some experience with this situation. Here's my take:
Most importantly, do NOT have an affair with your ex. She may be your soulmate, but you have to keep your hands off of one another while you're in committed relationships with other people. What you have together is lovely, but more delicate than you think, and it would be tarnished beyond redemption if you had a tawdry affair. Respect your love and yourselves.
Now, with your current marriage, I can see why you feel responsible for your wife. You're so much older than she is, and you've taken care of her for so long that it seems cruel to toss her out into the world. What's actually cruel is wasting any more of her precious time on this Earth in a marriage to someone who doesn't love her more than anyone else in the world. Do you hear me? You are wasting her time. You can protect her from the world, but at what cost? Please understand that it's costing her as well. She's got a soulmate out there too, since you believe in such things, and you're standing right in his way.
Regarding the money, have you ever heard the joke "Why is divorce so expensive? Because it's worth it."? A good lawyer is also worth it. If you're living in a community property state, she's entitled to half of what you've accumulated while you've been together. I don't think there's any getting out of that, unless you can catch her cheating on you, which I hope you don't because I imagine that would be devastating.
Your ex is going to have to get out of her own marriage. You can't do this for her.
I must reiterate how important it is that you both free yourselves from other commitments before even considering getting back together. It's important to do it cleanly. I think Pizza Guy's right about guilt- it will **** you up.