If you think option 3 is the best, then take the step. Don't worry about the future of a job. You will deal with it when the time comes. There are plenty of single dads out there doing the parenting, cleaning, job thing all the time, I am sure you will manage.
So say, I will move in. I will look after the children, it would be my biggest pleasure to do so. I will stay until end of Nov and manage everything. You (W) can stay at your parents' house or whereever. It's none of my business anymore. We can work out a schedule when the kids can see you. I am looking forward to this big adventure with the children.
Mark, you will probably never get to spend this much time with the kids again especially when you get a job, when kids grow up and have their own lives.
This REALLY is a gift for you. Take advantage of it! Look at this as a once in a lifetime opportunity for you. Not a tragedy that W has moved out.
Me:39 H:40 S:9 D:7 First Bomb ONS:June 07 Second Bomb OW: March 08 Separated: March 08 M:15 yrs T:18 yrs H deep into A with OW Achieved ACCEPTANCE May 30, 09