I don't think these two approaches are entirely mutually exclusive.
I agree that Sue needs to stand up for herself and let H know she will no longer be treated like a doormat. But the most constructive way to do that is through "loving detachment". Tell H you are not going to stand for his BS, and show him with your actions that you are serious -- by GAL, going dark, and not giving him the impression you condone his bad behavior. Put your focus on yourself and your needs, your survival and your well-being. H is certainly focusing on his wants and needs, at Sue's expense even.
I think it's okay to show H that you love him, but do so in a tough-love way. State your case, your disappointment in his behavior, and move on. H's natural reaction will be that you are raining on his parade. He will accuse you of being selfish and mean-spirited, even when we all know this crisis really stems from his petty selfishness. You just have to press on -- be kind and understanding, but don't give in to his childish stunts and demands for drama. Lovingly detach and put your energies into you.
Side note: I have to relate this to the experience I have had a couple of times with my six-year old. I was in the grocery store just the other day with S6 and S2, and S6 saw something on the shelf he wanted badly (some chocolate chip muffins). He grabbed the box and placed it in our cart -- and I told him no. He threw a tantrum and said he really wanted it, but I would not give in. He blew a gasket and had what we call a "melt-down". I told him I already had a dessert ready back at our apartment, and made him place the box back on the shelf. Then I told him to follow us onward. He refused and sat down in the aisle begging me to let him have his way or he would not move. I got down on one knee and told him under no circumstance would I allow him to have any such dessert item now, especially because of his poor behavior. I told him I love him, and his behavior was disappointing. I walked off down the ailse with S2, leaving S6 to complain after me that he doesn't ever get what he wants. (As if!) Well I rounded the corner and waited for S6 to come to his senses (kept a stealthy eye on him). Eventually he followed up behind us and was resigned to behaving properly.
This is something that parents often encounter in raising our children. It has occurred to me, now, that our WAS tend to act like spoiled children themselves at these times. They want what they want and blame us when they don't get it on their terms. I think we have to be strong and figuratively walk "around the corner of the aisle" till they come to their senses. And yes, it's a little scary doing this, even if it is for their own good.
