There is a lot of bad advice here as far as I know.
You don't need a d deed poll to change a middle name to first name.
Deed poll is for surnames.
OP you have made a mess of this.
My brother has used his middle name for over 20 years as the name he likes to be called by- he just told everyone at work and friends, one day.
BUT all official docs show his name as registered at birth.
Like John Henry Smith- but everyone calls him Henry.
I have known loads of people who are called by their middle name BUT they never ever had it changed on official documents.
For your passport you have to use whatever was your birth name on your birth cert.
As others have said, your marriage cert is incorrect. That's the error.
You see, for genealogy purposed later on, if someone is searching for a family tree or for any other reason, and for things like passports, all names have to tie up.
Have you spoken to the passport office or been in person?
I don't think anyone here can advise what to do next but deed poll won't work.
Speak to the passport office. Maybe you can get your marriage cert re-issued in your correct name?