Oh my you sound a very caring, supportive and loving partner. How lovely you are.
I'm not sure what resources are out there that can help you to answer or give you the solutions you seek. What I can give you is my own experience -
both my partner and I have varying degrees of PTSD, anxiety and depression. Thank goodness we don't always have it at the same time.
my partner is the one who likes the plans and the organisation - i.e. when and what time we leave, where we will stay, how long we'll stay etc.
me, I'm the exact opposite. Happy to pick up my bags on the day of leaving - go to the train station without knowing when a train was leaving, where we'd stay that night because I knew that hotels would be open to pop into, even in a country where we didn't speak the language.
That's just setting the scene for us. My partner can't really plan and organise - I have to do that even though I hate it with a venegance. Turn him around in an airport on his own, he freaks. So I do have to help out and make the arrangements without making him feel like he is useless. I guess I do this by not making a big deal of it, by just giving him all the information and making sure he knows where all the info is, flight inventory, accommodation details, getting maps for areas where he'll land. Sometimes I get all this together then sit down with him to go through it all. At times he does get defensive, but with a little cajoling and loving we get there without him feeling to useless.
Some people are good at planning and organising, others aren't. Some need a hand and I think it's okay to give a hand.
It sounds like your partner may not have wanted to travel on her own. Maybe reassure her this is okay, because it is okay?
Not sure if this has helped you or what you're looking for Shelter. You seem to be doing an awesome job of being a partner. Keep it up!!