What you were feeling in your dream was "success." This may be a warning that there is a very intense emotional THRILL when you have SUCCESS in getting him back from the other woman he's married to now. You walk on eggshells, but you might (some-fine-day) be successful at getting the upper hand over anybody else that wants him--Can you identify with the thrill of living dangerously by getting back together with him with you having the upper hand (as long as he's in a good mood)? The hidden lure of an abuser like him is that there's always a chance you can keep him from hurting you if you handle him JUST RIGHT--and perhaps you're the ONLY ONE who knows how to handle him just right!
It's possible that your unconscious is showing you that you're still attracted by the thrill of living THAT dangerously. Since you're safely divorced now and he's safely hooked up with somebody else, you can afford to fantasize about having another crack at managing his dangerous moods so well that you can admit that you want to have success with him. The mere fact that you know even in the dream that your success would always be short-lived gives you the thrill of living dangerously.
Let me know if you relate to this lure of the dangerous tension with him, that perhaps you've not been able to find to the same degree in any other way--or in any other relationship.
Why are you trying to gain the ability of lucid dreaming? Do you want to have control over the return to super-tense-reunion-with-ex and experience being ABLE TO HAVE THE CONTROL OVER HIS MOODS THIS TIME?
That would be equivalent to returning to the nightmare you lived for most of 17 years (probably not so much at first, when there may have been high-energy "paradisical love-life"--tho that's not necessary. For any full-on respite from the abuse cycle could feel like "-paradise regained.") You'd be returning to the nightmare and controlling it so you can have the thrills & success without the return to nightmarish fear and abusive reality that always came back in real life. So you urge to master lucid dreaming could then reflect a subconscious desire to gain the upper hand in the battle with emotional terrorism. And THAT is the hope that keeps SO many participants in abusive relationships returning in life or in reverie to try again to win their return to the love they thought they once had.
For love burns more brightly in adversity, even if the adversity is itself toxic to one or both partners.
I did not suggest you would take him back. But in your dream your ego is trying to WIN. REVENGE is the subject of recurrent murders in many primitive and modern tribal rivalries. It is precisely the (grossing-out) DIFFERENCE between what happens in your dreams and what your waking ego feels and wants that provides the insight into the unconscious power that such adversarial relationships have in both LOVE and WAR. It is an inborn irrationality of human nature, NOT a fault of any of the millions of us that stay unconsciously stuck to such emotional intensity. I AGREE with your conscious desire to achieve a lucid dream-state in order to kick his ass, because that would be a perfect symbolic enactment of re-empowerment for you by subjugating him the way he previously subjugated you--also much healthier if done in your dream-reality than if carried out by a real physical attack. (For getting revenge in real life runs the risk of setting off a recurrent cycle of revenges that perpetuates hatred between families, tribes or nations.