I will sell the house and move in to a small apartment, or work 2 jobs if i have to. Money is one part i'm concerned about, but there is also the emotional, physical, mental fear to do it alone.
I know someone who left her abusive husband and had to move into an apartment. She had to seriously downgrade her lifestyle and her child's. The father is still affluent, but at the end of the day the kid prefers to be with the mom.
If you stay with him, you have to financially prepare yourself for a relapse and another job loss. Fortunately, they would be the same steps for your own financial preparation if you decided to leave him. So working on your career and saving is NOT necessarily a decision to leave, and you'll have time to see whether or not you want reconciliation or not. As they say around here, hope is not a plan.
That said, I can speak from personal experience that if your children are motivated enough, they can find money for college. If it gets drilled into their heads that you won't be able to contribute the entire amount, and if they hustle, they can figure out a way to afford it. And if they're Ivy League material? A number of them offer FREE tuition for families that don't make enough. (ex. Harvard provides a free ride for families making less that $65K). There are also kids who go to community college for two years with automatic transfer to a 4 year college. They save a considerable chunk of change.
Don't let future college expenses, especially if they end up being way less than you imagined, determine what the next steps should be.