Negative for HIV but I've heard that HIV can take 6 months to show up in the body. Should we continue condoms?

Not sure understand. My assumption is that you were exposed to HIV in some manner (unprotected sex, needle sharing, etc.), and are using condoms to protect your current partner. You don't say when you were first tested and what follow-up testing has been done. My recommendation would be to continue using protection until you are sure you are not infected, and your doctor can help with this assurance.