Bf & i are in a monogamous relationship (1yr). had sex 2 nights ago (sex many times b4). now hes itchy inside/on tip of penis. my vagina is too. why??

Yeast infection?: A yeast infection is the best bet for this situation. If you're sure STDs aren't a risk, i.e. neither has had other partners recently, you could try an over the counter vaginal yeast cream, which your partner could also apply to the penis. But see a doctor if that doesn't clear things up in a few days. Look for any cream with active ingredient ending in "azole" (miconazole, clotrimazole, etc).