That's good you going to find some counselling. It will give you a safe place to work things through.
I remember being in utter turmoil daily, crying in my car and pulling it all together when face to face with people. It does fades in time. I was told a month for each year together. Be kind to yourself. Remember to eat. Sleep and don't feel like you need to be super mum. Kids fed and safe. You are doing all you can.
Sort the house out. Get his things together in the garage out of sight. Move things around. New bedding and paint if you have the energy.
Stop engaging with him and ow. They are none of your concern.
Three things you need to engage about
Contact with the children. How old are they? Once they are a certain age they get a say in contact. Do they have phones so they can maintain contact independently. Set a routine eow. If he misses his weekend tough until the next one.
House/divorce. Through solicitor
Money - through the CMS.
I know you are hurting and looking for answers. There aren't any except he is selfish.
I found writing things down helped. If you need to engage about something. Write it out. Sleep on it and edit it. Never respond immediately as that will be fuelled by emotion. Make it business like
My ex wanted to be friends. He couldn't see how his actions turned my world upside down and he thought I should of been thanking him for 'setting me free'. Ow was there from day one. I refused to make a fuss. That's what he wanted to show me as being unhinged. My rule was as long as the children were safe and she was kind then I would not react.
Just go day by day. You know in time this will become more bearable. You just got to get to the other side. The children and I have a really happy life together now. I wouldn't change a thing. You too will get there.