If the time comes that someone needs to leave for any reason, most agree that the one wanting to end it all should go. I did not do this and regretted it later. I hoped leaving her in the house with the graduating sons would help her find her way back somehow. It didn't help anyone, and made things worse since she didn't "want" to be stuck with the house, or the kids.
Sounds like your H is having some mid life confusion and that takes rational thinking out of the picture. Trying to reason with him can be like argueing with Alice's looking glass. He is on the other side and no longer recognizes reality. It can completely turn the world upside down for everyone in the house. Cut 'em loose. It may wake them up, or not. Nothing helped my X, since all she ever really wanted was to be an X, and play grown up Mystery Date.
The most important thing for you to do right now is focus on taking care of yourself, the kids, and your perspective. Learn that success does not always mean saving the M. Success is also what you make of a terrible situation, and how you live your life in the face of insane chaos.
Hoping you find great success in your new journey.
