If you tell her you want to leave, and you have provisions for helping to maintain the home you live in, and you pay child support (if you have kids together), then abandonment is not an issue. She can NOT prevent you from seeing your kids—period.
My suggestion is to go to a lawyer, have a separation agreement written up outlining visitation, and financial provisions. That way, you have documentation that this separation is not ‘out of the blue’ and that you’ve made provisions to not leave her ‘out in the cold’ (ie: abandonment).
Now…the tricky part. She does not have to sign it (and from what you describe–she probably won’t). I don’t know your financial situation with mortgages and such. If she works, then she is responsible for part of the obligation. If she does not work, then you may be setting yourself up for a huge financial load with alimony and mortgages, bills etc.
It sounds like your wife needs some SERIOUS mental health. She has already threatened to use the kids and I believe she probably will if she is so adamant about you ending the marriage. Her anger management may come back and bite her in the ass if she doesn’t address it, and I would certainly mention it to your lawyer.
BOTTOM LINE: Get a lawyer’s advice and paperwork done to put on record a date of desire to leave.
My situation was similar. I had an agreement in hand for 4 months. She would never sign it-so I finally left. My agreement showed evidence that my intent was to leave 4 months prior and I had provided generously in the agreement so abandonment could not be an issue. My life was miserable for those 4 months (and several years prior). It has been hard, but emotionally, I’m in a MUCH better place. Be strong.