Wow I've been there, done that....lose my mind guessing when H is gone, when he's back I feel more sane...calm that I know where he is and what he's doing. It's a horrible process but at some point it has got to get easier.
Your summary for H's return is a good start...just remember to stick to it. It's great that if he makes it back for the party you can use the party as a bit of a distraction, easier to act AS IF when you're busy....and H can see what a Supermom that you are! Have fun, fun, and more fun...and if H wants to join in then all the better. Really hope he makes it to your S's party and doesn't need to fly off immediately.