I would first try to identify the source of your problem--is it the room, or is it equipment related? Try setting up the system temporarily with the speakers somewhat away from the walls and your sitting position fairly close to the speakers (say 5-6 feet from the speakers). Experiment with the exact position to get the best sound possible. In this position, you are listening in the "near field" (position where the direct sound from the speaker is predominant so the room's contribution is diminished). You are now listening to your equipment moreso than the room. If the system sounds worse this way, you probably have equipment issues. If it sounds much better in the near field, you have issues with the contribution from the room.
I have generally found that it is too easy to go overboard with room treatments, and very few treatments, apart from major room rebuilds, look decent. That means you should take things slowly. First, experiment with correct placement of the speakers. You can make huge changes in the sound just by using different placement (distance from back and side walls, toe-in angle, backwards rake of the speaker, etc.). If you want some kind of systematic approach to finding the rough placement spot (experimentation is ALWAYS required to find the best spot), google the Sumiko method or Wilson method for two decent approaches.
Next, I would try very modest "treatments" that won't send your significant other running from the room. Look for nice tapestries to hang on the back wall (behind the listener) and for the side walls. This is usually enough to significantly reduce slap echo brightness without dampening the life out of the room. Experiment with a blanket or comforter, etc. Again, go slow and give yourself time to adjust and experiment with each addition/placement choice. Bookcases/cd rack/record racks along the side walls can also help to act as diffusers and rooms with such lining the sides usually sound pretty good.
If you can, either remove or cover the big ottoman to reduce its impact on the sound. A big reflective surface between the speaker and the listener is usually a major detriment to proper imaging, and if it is highly reflective, it can also contribute to bright sound.
