Pain, I think the feelings you are experiencing toward your W at this time are completely normal. You still care for her as you would anyone else who has shared part of their life with you. You are probably seeing her from an emotionally detached position, which is fine. It may seem a little strange, but it's okay. The "payback" thing is probably your anger speaking to you, which is normal, too.
I feel confident that you are a man who can do the right thing, while keeping your emotions about the MR out of the equation. If this had happened a few months ago, you might not have been able to wort off any emotional confusion or have outcome expectations. You've learned to not try and turn things into more than they really are. She's in physical pain, and she may be down until her back gets better. She may need assistance until she gets better, IDK. Whatever comes...….you are going to conduct yourself with strength and honor.
You've got this!
It is not about what you feel should work in your M. It is about doing the work that gets the right results. Do what works!