Kevin - this is the second major life thing your W has done in less than a week and did so by "bomb dropping" on you.
First, after mucking up the plans last weekend to suit HER schedule she casually drops the news at a b-day dinner for her own daughter that they are moving. Your kids had no clue, you had no clue. Your W had no respect for you as a "co-parent" to even discuss uprooting the children or at the very least letting you know the plan before the children were told.
If she wants to take you off the insurance, well, fine, her choice. She certainly can find the time to text/call you when she needs something but didn't feel it was necessary to tell you about the insurance until you got a letter in the mail. No respect.
Now her bills have decreased as you said COBRA was less expensive, your bills remain the same and YOU are without health coverage and didn't find out until after the fact. Not to mention during this time you told her you would financially have her back. She wasn't really worried about "your back" when she took you off the insurance w/o advance notice so you could find your own.
I guess what I am trying to say is look at all that disrespect that happened over the course of SEVEN days and what is the end result? A movie.