Suggest Medication For An Infection In The Vagina

my husband and I had vaginal followed by anal sex the other night. later the next day he noticed red rashes around his penis, then this "rash" spread to his scrotum as well, but it does not itch. I have vaginal itching--thinking this was a yeast infection (I have had them before) I treated it accordingly. Now I still have vaginal itching (I am using vagisil to treat it), and he is worried that we have somehow contracted an STD (we are monogamous though).