Please read and post to Mrs.Nop's post!! I am curious about your every day interactions with your wife too. What things does she say to you? Does she make you breakfast? Does she ask what you want for dinner? Does she thank you for helping her??? ETC.
Also you characterize it that your wife became LD and then adopted the LD personality. What if it was the other way around? Your wife lost joy and fun in her life and THEN her sex drive diminished. Would that make any difference in how you view her "issue" and how you might look to solving your problem??
But what is happiness except the simple harmony between a man and the life he leads? ~Albert Camus