Do you want to close and move on from this marriage? If yes, then I would give one months notice to your dc families. If you don't want to close and yes to ending the marriage, I would stay in the home as you are still contributing to the family unit even if it is fractured and ask your spouse to leave. The marriage ending does not mean he has to lose his job right?
If you want this marriage to succeed, I would make a strong attempt at counseling. My first marriage broke up so I understand the stress and the pain you must be feeling. Even if the marriage does not survive, if I were you I would pursue counseling just for you then to help you deal and sort your feelings. I did, and I know I was able to move on much faster than if I hadn't spoken to a proffessional.
I send you hugs and wishs for you to have strength and wisdom in all the decisions you must have to make. Good luck hon