Does anyone think I just put the final nail in the marriage coffin?
No, but I think SHE may have. It is not YOUR REACTION to her poor behavior, but rather her POOR BEHAVIOR ITSELF that is putting any "nails" in the marital "coffin" here, QS.
You need to let her go, QS. This is where I disagree with Allen, as much as I admire and respect his work here. I do believe that there does come a time for Robx's/Gucci's "I agree"/let them go speech.
At some point, this just becomes so much CONTROLLING on your part, trying to convince them to stay in the marriage. There is wisdom in that old "If you love someone, let them go" saying.