Acapella,
I am sorry to see you in so much pain but at the same time I see strength in you more than since I've known you (Echo.).
I certainly understand your fears. I've never been divorced, and I can't imagine haven't to contemplate leaving my husband. I did leave a fiance that I lived with for three years however. I would say though that you are beginning to follow your gut, and your gut knows that this man is not likely to willingly change, or even if he did temporarily, it might not prove to have longevity.
As Seeker suggested, couples counseling is always my first thought... but didn't you try this before? Maybe I am confusing you with someone. The problem as we all know is that most Ns are capable of snowing over the therapist.
My N mother went to some counseling several years back to deal with grief about my dad's death and worked a little on herself. It didn't last long, and the result was this: She is now able to identify in herself that she is emotionally immature, but the behavior has not changed. She can be reminded that she is hurting me (or someone else), and will apologize... but the behaviors continue because she doesn't know any other way and can't (won't) change. The moral of the story? A true N is incapable of EMPATHY. Acknowledgement is helpful, but as someone else suggested, is an N ever truly capable of healing? That's even assuming they want to! She continues to use, manipulate, lie, hurt, and control, even if she feels bad about it later (which I don't think she does other than in principle - it is more for fear of losing those that are her admirers).
So, the options become, if we are comparing it to an N situation, as I see it:
1. Accept this man for who is is, love him unconditionally and learn how to distance and protect yourself with boundaries. But true intimacy will be almost impossible. If you bring children into the marriage with him later, you will be doing so knowing you may have to protect them or teach them how to protect themselves from his N behaviors. Can you experience peace within yourself under these circumstances?
2. Accept this man for who he is, and love yourself unconditionally. Acknowledge that you cannot change him, and decide you want to experience true intimacy and peace elsewhere.
3. Decide not to decide now, but take a moving-forward action: remove yourself physically from the picture (since there are no children you are lucky to have this option) and take time to be apart and decide. Go to counseling together, and apart. Use your intuition to see if his behaviors change if he promises to. Learn how to distinguish between geniune change and manipulations.
I think a big part of why this is harder for you than past relationships is probably age. I know that I would have had more strength to "bounce back" at 25 than now at 36. Our lifestyles change. We get comfortable in our 30's and later. We are mature, we are homey, we're not out clubbing like we used to. We fear "will I ever meet someone again?" or fears about that the pickins get more slim as we get older (with age comes more "baggage"?)
The good news is - because of the experiences and maturity.. we become less needy, don't we? Especially us here, because we are healing. When you met your now husband, you were probably needy of him in ways that were subconscious. I think what you are experiencing now is that you might not need him like you used to! It doesn't mean you don't love him, but you might recognize that some of the love may have been immeshed with need. If you leave him, you probably won't feel the "need" to replace him, because of the growth you've done. You might find peace within yourself - and healthier people will be drawn to you automatically. It is under these circumstance that I met my now husband, whom I am happy with and when we have problems is healthy enough to work with me (sincerely).
So, that is a lot of lip service for me to be giving considering I've never been in your shoes. Please take it with a grain of salt, or tell me to go to hell. whichever you feel, I won't be offended!
Whatever you decide, I am here and supportive. A very big decision indeed. Good luck with your ponderings.