Center the bed on the wall, for sure. Get a chair, or chaise lounge for the bump out windows. Add full length drapery panels on sides of these windows. Put the tiny table near that chaise/chair, along w the standing lamp. Find a complementary table (complimentary in size and color) for other side of bed, then put large, chunky lamps that match on both sides of bed tables. If the height isn’t the same, put books under the lamp to make the lamp heights end up the same. Finish with a large horizontal piece of art over the bed, pillows in same colors on the bed and one on the chair, or chaise. Voila!

You have a pretty room but, apart from the painting, there are some issues to consider. Your curtains are too long, which affects the impact of the room negatively. The mirrors above your mirrored side tables with the crystal lamp bases are too much of a good thing. Find good-quality vertical pictures to hang there instead. I would leave the horses where they are, which seems a perfect spot for them. I would probably leave the bookcase there too, but it would need to be filled with books. There is hardly a room in the house that doesn't look warmer and more interesting with some books. The patterned chair would look better away from the patterned curtains. You could still hang a smaller horizontal picture above the bed. If you have oil paintings over the side tables and a watercolor or drawing over the bed. Can't have too much art in a room in my opinion. This room seems to call out for some warmer colors like yellow or red to balance the blues and grays, and those you can incorporate with the art you find. Try e-bay for genuine art rather than prints, which won't give the same feeling. I loved the first photo with your husband? holding up the picture. Mine has had to put up with that so many times!

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I fully agree that you don't need to fill all spaces. This area is a candidate for doing absolutely nothing. Obviously, a lounge chair or any chair would ever be used in this setting. However, as I look around the room I don't see an area where you can throw a robe or put on socks. This is why I suggested a small bench.