Hi op
Would you find it useful to give your anxiety a name?
What I mean is pick a name of someone you dislike or a name that would be disparaging ..like fuckwit or dickhead etc
So this thing anxiety is a regular unwelcome visitor, so treat it as such, talk to it make it a separate entity to yourself who is unwelcome and a pain in the arse.
Make it list the things that could go wrong, then come back with your points where it won't, and if it does what can be done to mitigate that issue.
Also I maybe wrong but have you got set days and times you see your partner?
Has the anxiety got an appointment for these set times to come visit ?
If so can you slightly change these timings to put anxiety on the back foot?
If this all sounds strange to you, my point is to take control of anxiety as if they are a real person that's annoying you. If it was real what boundaries would you put in place to minimise contact with this person.
When you get to that day of the week when you know it's coming, talk to it
I'm hoovering right now you'll have to wait, or I'll see you at 6 tonight but you've got 5 minutes and that's it. If you can train it, the anxiety treat it like a naughty child or irritating fly, over time you can decrease the power it has over you .
It will take a bit of time, and as my Dad would say throw a few fucks at it 😳
Tell it the stress it's causing you what a waste of time it's been, and your not standing for it. Imagine a big steel box, and practice locking it in there every time it pops up.
Ask you therapist about guided imagery, they are very relaxing and allow the unconscious to come through with any issues.
Good luck lovely