The beauty of GAL is - if you walk the walk and talk the talk long enough, you eventually begin to really feel ok if he stays or goes. Showing H that you will be happy either way is one benefit. It will make him look at what he is losing by getting a D. The other benefit is, your life is fullfilling for you no matter what he does.
And setting boundaries is tricky. Doing it without ultimatums is the key. I'm working on that myself (if you check out my thread). It's a fine line but it can have an effect.
