Wow,this thing has played out almost exactly as I imagined, right down to her inviting you back to be the live in babysitter. This lady has skills, I will give her that.

However my opinion doesn't matter, if your happy to be home regardless of her feelings toward you, then I wish you all the best.
I will say growing up in a household where one parent deeply resents the other, sucks. So keep things super easy going around the kids, cos they will learn how to be in a Relationship from how you two interact with each other.
Take Care and I hope it works out for you I really do.