I read your other thread. First of all, run, don't walk back to your house. It was a huge mistake to leave your home and could cost you custody of your children in the future should your H decide to file. I wouldn't call him about it. I would find a time when you know he is not there and move back. If you are worried about his reaction, take your sister. If you don't want to share a room, find another one. When he gets back simply, calmly explain that you realized that it was a mistake to move out of your home and your children need you. He will be angry. Don't engage in it. This is about your children. Of course, if he is abusive in anyway, take you kids with you and go to a shelter. They will help from there.
I would also print out whatever you've found on myspace. Don't share it with him just yet but you may need it later. If you don't have hard copies, they will just delete the incriminating posts and call you crazy which we all know you are not.
As for needing to support yourself alone if he leaves, he will still be on the hook for family expenses. Leaving does not excuse him from his responsibilities. Seek some legal advice. Don't tell him about this. He will see it as a sign you want to D.
Finally, don't lose hope. What you're going through is pretty typical. Even though it doesn't seem that way to you. Read the websites above, get the DB book. I always recommend Dr Phil's Relationship Rescue. It goes really well with DB and has great communication techniques. Best of all, just like DB, it can be done without your spouses help or knowledge.
Remember that when a man loses his job, it is devastating to his self esteem. Some react like your husband has. You have to remember that it's a phase but it could last a while. Just continue to GAL and detach. That will help you keep some sanity in his craziness.