You CAN have HSV-1 (oral herpes/cold sores) in both places.
HSV-1 can be transmitted to the genitals via oral sex. It then becomes HSV-1 of the genitals, which is a different TYPE of herpes simplex than HSV-2 (genital herpes), although the symptoms and outbreaks are indistinguishable.
The ONLY way to tell which "type" of the herpes you have on your genitals is to have a viral swab taken of a sore within 24-48 hours of an outbreak--no later! After that time and the results are not reliable.
The other option is the IgG type-specific herpes blood test, which tests for BOTH HSV-1 and HSV-2. While it cannot tell you whether the HSV-1 infection is orally or genitally, it can help you find out whether your boyfriend actually has BOTH herpes infections and is asymptomatic (has no visible symptoms) of HSV-2.
It is not at all uncommon for men to have an HSV-2 (genital herpes) infection and to not exhibit any symptoms. They often discover they are infected ONLY after taking the IgG blood test.
The trick is in the timing of the IgG. If you are infected, antibodies for the virus will show up in the blood 2 weeks-4 months AFTER you are exposed to the virus. The timing depends on the individual's immune system and it's ability to fight the virus. For that reason, many people do not show antibodies early on, so it is best to take the test at least 3 months after you suspect you became infected, which will give you the most reliable test results without having to run repeat tests.
Think it is time for your boyfriend to get tested, too. Oh, and you should know that STANDARD STD TESTS do NOT include tests for HIV or herpes! You have to specifically ASK for them--and pay extra to get tested! If your boyfriend has never been tested--it's time!