I have two words I can't believe I didn't see anywhere else in the thread: Love & Respect (
Google this)
If she's a decent woman with honest and good intentions, then she will respond to love. It could easily be something about your marriage and the way you interact with her that leaves her feeling as though you don't really love her.
Definitely, you are seeing disrespect from her. Disrespect is how a scorned woman will respond to her husband if she perceives he is being unloving. She's communicating it loud and clear to you, although she may not know why she is having these feelings or that it stems from not feeling loved by you.
I wouldn't be quick to place the blame in this damaged relationship. Every married couple I know goes through these phases of hurting one another. Things he does makes her feel unloved. Things she does makes him feel disrespected.
What you perceive as a power play (the threatening of divorce) is actually not as bad as if she began to cut you out of her life entirely and had no verbal communications with you. Her use of the divorce mention might be her way of probing to see if you're even still interested in continuing the marriage.
So before I began any divorce proceedings, I would at least give the book a few chapters of reading and try to talk to her about your relational difficulties. You may be surprised to find out that she hasn't felt love from you in many years. Men can do this and be completely oblivious to the fact because for most of us it's not our first nature and not at all how we prefer to relate with one another (feelings).
If you want to, please feel free to reach out to me to chat more. I think every marriage has the potential to be salvaged predicated on the fact that you have decent and good willed people on each end of it. It takes a special kind of character to intentionally enter into a marriage with the sole intention of abusing and wrecking it.