Can't remember a book title!

Ah! How many times has that happened to you guys?
You're sitting there, thinking about this great (book/movie/show) you once experienced, and you remember so many elements of the plot... but the name just won't come to you!! AHH! It's making me crazy!
Let me tell you what I can remember about it, and maybe one of you have read this book. I am pretty sure it's a historical romance, and I'm pretty sure it's not by one of "my girls" (i.e., Jo Beverly, Gaelen Foley, Sarah MacLean, or Christina Dodd). Please help if you can!

There's this woman, she's a governess (of sorts) and someone that she knew for years (a Duke) cajoles her into agreeing to teach --what she thinks--is a younger boy. Turns out, he's a grown man who has recently been paralyzed, and he's having a really hard time adjusting. So, having experience working with difficult people, she tells everyone to stop catering to him and she takes him out in the fresh air for some alone time. She wheels him out there, and he's being a total jerk to her, so she leaves him outside and tells him to find his own way in. He does, struggling the whole time to wheel back to the house, and when he gets there everyone is super nonchalant, acting like it was no big deal. 
All right, then, the Duke has this factory? Mill? Some kind of fabric or textile venture? And the women from the lands surrounding the house are working there. Unfortunately, they are having a hard time getting the business up and running because all of these "accidents" are occurring, and the Duke can't figure out why. Also, FYI, the Duke has been having a love affair with the housekeeper and they have a 10-year old daughter together, but the housekeeper refuses to marry him because she doesn't want his title sullied by being with her, so they keep their relationship a secret.
Moving on! Turns out, the guy in the wheelchair is technically not paralyzed, though he doesn't know it. He's been sleepwalking through the house, going outside, etc, and only his valet knows.... or so we think! People think they are seeing the ghost of the old Duke and when he sleepwalks, bad things happen around the manor. We realize that he feels super guilty because he thinks he's the one hurting people, WHEN IT'S REALLY THE PRIEST!! When there's a major accident at the mill, the guy jumps out of the wheelchair and tries to save his brother, who is killed in the wreckage. He's no longer unable to walk, and he takes over the dukedom and tries to get the mill up and running like his brother would have wanted.

Is this ringing any bells for anyone?! Ah, it's making me crazy!!

Thanks for all of your help!