Having unprotected sex with two different men, I always get yeast infections. Why? And what can I do to prevent it?

Chronic Yeast . There could be several causes for this. It could be coincidental to sex...And be from something else you are ingesting. It could be irritation from the lubricant or the condom. You may be allergic to something and the irritation in the vaginal cavity reacts with a yeast overgrowth. Your gynecologist may need to do some testing and to put you on effective treatment.