It's good that you have patience, so now let's see if you can go without bringing up the R to your W.
You see, talking it over with her doesn't fix it. You are wanting to talk about the problems in order to fix them. I am exactly the same way! However, it doesn't work, and in fact....it will push her to make a hasty decision to D. So, leave it alone.
Your W is worn out. She's depressed and I'd bet she feels lonely. She's given up hope for the M getting better b/c she thinks she's had to do all the work. That's another reason you should not discuss R or ask her questions about where she stands. Right now, she's trying to do what she thinks is "right" by staying and giving her kids a two-parent home. It's the kids that is keeping her planted.
I would suggest that you back off trying to get her to go to MC, for the time being, b/c it will not help if she's not willing to work toward a better R or make changes. She's disinterested and she's worn out.
I remember so well how I felt when I decided to stay in my M. Was I happy? No! Was I ready to give 100% effort that my H asked from me? No! I had to reach a point to where I was just willing...to be willing. Make sense? Probably not, but I bet your W would understand completely b/c of her mindset.
"but she must be considering MC because she wasn’t sure if she wanted to talk to someone because if they told her SHE needed to do something differently that would just p@ss her off."
To me, it sounds like she's telling you the reasons why she doesn't want to go.
I would suggest that the two of you find help with how to co-parent, instead of MC, since that seems to be a critical area in the R and is her basic reason (co-parenting) for staying.
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!