Right, this has been keeping me depressed for far too long, nearly two years ago now, my now wife was having some problems with her "herself" whilst we were having sex, she said it was far too painful and stung when she had to pee, she went to the doctors to find out she had thrush, it never went away so she went to the hospitals sexual health centre to get tests to find out she had herpes! I got tested too to check and I was clean, and the first thing that popped into my head was ,"herpes? STI! she cheated and yet she has been adamant that she never did, but also never fully said what the doctors told her, she did say that they told her that her thrush had "turned" into herpes, now, am I an idiot for believing this or can it actually happen?
Thrush is a fungi infection... Like yeast infections That doesn't turn into herps.. Sounds to me she is hiding a lot more and your health is at risk.
Thrush does not "turn into" herpes. This - and your relationship - probably needs proper investigation together.
Hi, it may be a good idea to research all you can about Herpes as well as speak with a Doctor (at a GUM clinic perhaps) to learn about the virus.
For instance: Most of us have been infected with the virus, and many of us with no symptoms. The Herpes Virus can lay dormant for many years and then just erupt out of no where. So it is also possible to have been unknowingly infected long before starting a relationship with someone - and the virus can erupt years afterwards.
However, the incubation period for many STI's could be a definite give away for infidelity. So if an STI should show up then that could be proof of infidelity on someones part... Not so much with a virus that can lay dormant.
It is not likley for thrush to turn into Herpes, it may have been a misunderstanding. Good luck
I personally would go mental! Sti and cheating instantly pops into urn dad! But.... I have heard before that herpes can lay dormant in u for a while, never having any symptoms then all hell breaks loose. I'd honestly go have a chat with some one at the clinic who knows the truth on this. I'm not sure how long it lays dormant for and I guess even if it did it depends on how long uv been together. Good for u that u tested negative though 
good luck