The most likely would be Herpes Simplex 1 or 2. If your partner has herpes, this can be transmitted to you rather easily. Not quite as common for female to male transmission would by HPV. If your partner had the virus in their mouth or throat, then this could be transmitted to you. Might I suggest using a barrier method when giving and receiving oral sex? You can use a latex condom for protection and there are dental dams available for purchase too.