I think we all tried to stay out of this forum. It's a horrible situation to be in but the D/S gang is so wise, kind, honest and experienced. I am sorry that you find yourself here but know that you will be supported.
Your dday is so recent so your pain is extremely raw. You are starting on the right path to healing and rebuilding yourself by starting the 180. Are you in IC? Do you have support IRL? Do you like to read book? There are a lot of good books out there to help you cope, heal and rebuild YOUR life with or without him.
I would rather 100 days of pain with him than 1 day of happiness with someone else. <<< Reading this statement from you makes me sad but I understand where it is coming from.
This part is going to be tricky. At a time when your heart has been ripped apart, you also have to be able to think without emotions. You have to protect yourself financially. Just like you were shocked to find out your WS could betray you, it's just as shocking when they screw you over financially (child support, spousal support, joint credit cards, etc).
What I did, because I was a complete mess, I asked two people close to me but who could be objective and asked them to go over what I was asking for. I also needed them to come with me to my first appointment with my attorney. Just having them there, kept me focus. You have to protect yourself!
It feels like it won't ever get better but it does. It gets so much better. It takes a hell of amount of work and tears but you can do it!