"I'm wondering: perhaps it's not the D talking. Perhaps this is a passage couples in long term relationships go through" - - Book Lover

Not my experience at all. Married over 48 years. When the depression hit a little over two years ago, it was like that old movie "The Invasion of the Body Snatchers". A loving, intimate relationship of 46 years simply disappeared and all the classic symptoms of depression appeared in its place. With medication, things are better, but the closeness and intimacy is gone. As long as there is no stress or any demands on him at all, he is stable. He knows how difficult it is for me to give up all of that, and wants with all his heart to get it back, but it's like he's in a glass box and can't get out.