Finding my strength to follow through

Over the past 12 years, he has cheated many times. I recently found out he has had a year long affair ( he claims it was strictly emotional) with a coworker. He cut it off months ago and is begging me to stay.
Staying would be easy.
We have three young kids and we have lots of debt and I only work part time. It’s gotten to the point where I can either do what is best for me or best for the kids. He left us once, 6 years ago, and my kids sometimes talk about it and cry because they don’t want us apart.
My family says I need to decide, follow through, and make a plan.
10 years, and all my kids will be grown and out of the house. If i can accept that it is over, perhaps the pain will stop and we can stay together for the kids, but love separate lives.
I can also leave, but honestly I have spent my entire adult life as a stay at home Mom so I have no prospects of making enough money. With 3 kids, I have to be off by 3 and school holidays because I don’t have a sitter. My account has $200 in it. I obviously can’t hire a lawyer right now or get a deposit for a home. Does anyone out there have tips or advice on making a plan to leave? where should I start?