I would also develop a strategy. Consult with an attorney. You may want to start with someone with experitce in mediating disputes. Calculate your assetts and determine your worth. Watch money flow and locate important documents. Put a stop on joint credit cards. Since you had a company together you must have an accountant. Get your hands on those financial records.
This is not as intimidating as it sounds and it will also move your from a reactionary, defeatist mindset.
My wife ran away from our marrage and I realized that though I still loved her, I had to also proceed along a second track. It was clear that she had planned this months in advance. I had to play a little catchup but she had underestimated how fast I would respond and how thoroughly I'd cover every base. She was pretty shocked. She went ahead with her move but she no longer held the cards.