Totally agree with desert rat. Im not doctor and infact im new to this forum, but im not new to holistic medicine, which i find relies heavily on common sense.
Firstly if you have to come into contact with any nasty substance, orally is the way to do it. The acids in the mouth and stomach are so strong they can disable virtually any disease (even HIV). (note i say CAN kill HIV.... its probally not a good idea to put this to the test, especially if you have health concerns that mean your body might not be working 'to spec'
Secondly EVERYONE has candida in their gut, its only when it gets out of control that its a problem. Your partner will already have far more candida in their body than you will pass through kissing (unless you have very tough lips)