Libby, The reconnecting you witnessed where actually touch and gos. They do a lot of that and it usually is when they have moments of clarity. So expectations are at zero and keep them there.
As for him moving in w/ow, this should be very interesting because up till now it is only once in a while. What should you do about boundaries? How do you feel about him having full access to the house whenever he pleases? You may just come home one day and discover some things missing, etc. I would suggest that you set some boundaries and advise him that he is only to come over when you are home, i.e., call or text first. The same would apply to visitations w/the children. However, you are the only one that can decide what you feel is right for you and your situation.
Time for him to pack up his bikes and engineering tools and move them over to sweet cheeks. He needs to face the full reality of his soulmates' warts and all.
No matter how detached you are, it still hurts. Please take care of yourself.
Sit quietly, the answers will reveal themselves when you least expect them to. The past is gone, the present is a gift and you need to focus on today, allow the future to reveal itself when it is ready.