Have you been on Antibiotics a lot? Yeast infections can be caused by Antibiotic use. Try taking probiotics orally and probiotic implants (they can be found at most high end health food stores). You say your sexually active...is it a monogamous relationship? Yeast infections can be sexually transmitted. Also now that you have a yeast problem you and your partner may continue to reinfect each other. I used to have the same problem prior to my period...I always seemed to get sick during that time frame. However, I have Lyme Disease, and therefore, my immune system is weak. Currently, my Lyme is either gone for good or in remission, so my immune system has been very strong and I have not been ill for a long time.
Perhaps some others will offer some more tips for you.