Hi Jodie11,
Since you have done everyting you can think of, short of surgery, which I have never heard of for burning in the vaginal area. I would suggest you have your partner go in for testing. Perhaps the answer to the problem lies within him not you. Sometimes we could be carrying a high level of a chemical in our bloodstream that affect our partners, via our bodily fluids. Certainly wouldn't hurt to have him checked out. If he refuse, there is a red flag waving.
Good Luck,
Faded Rose