How about thinking out/talking out what you might in terms of "before care" and "after care" with your partner?
To connect and reassure before she goes and after she gets back?
Could some page 5 & 6 things help with the envy?
It's also the emotional management to dealing with stages of grief
(Because getting used to the "new normal" will take time) and with poly hell type things
so they are acknowledged and processed and not shoved under the rug.
I dunno if reading those could help you. You sound like you are trying to get a handle on it pretty well all things considered.
Hang in there.