i have had no history of candida then suddenly 2 years ago i developed candida which reoccers every month with or without medication (nizarol and diflucan)my question is this coincided with the start of my relationship with my current boyfriend.is it possible that he may have passed this onto me from a previous sexual relationship

Candida can be passed back and forth, so many experts believe it's a good idea to treat both partners. Have you also made adjustments to your diet and lifestyle? If your body is weakened and out of balance, you may be more likely to have a reocccurrence.
According to "The Body Ecology Diet" by Donna Gates, "A man's semen is alkaline, so after intercourse it is important to restore the acidic condition of the vagina. In addition, candida can be passed back and forth during sex, so the woman can protect herself by douching, then implanting with friendly bacteria or tea tree oil. If you do this regularly, besides taking other steps to heal yourself, it will work - you will have success."
Douche Recipe: 1/4 Cup apple cider vinegar in 1 quart of distilled or purified water. After douche implant friendly bacteria.

I've had good results douching w/ about 2 Tbls yogurt mixed into a quart of cool water.

If it occurs monthly then it's probably being kicked off by hormones. Many women's symptoms worsen at certain times of the month, near ovulation, near menstruation etc. It's most likely candida that's behind it which means that until you change your diet, and or take the antifungals, it will remain the same. For whatever reason, your body is weakened and is not fighting it off effectively.