How safe is it to sleep with a female with genital herpes, unprotected, she has not had a break for 3 months?

Not very safe. Unprotected sex with multiple partners is never truly safe. You are focusing on her genital herpes. However, by having unprotected sex, you are exposing yourself to every partner she has ever had. Do you know what other exposures she has had and what other stds she might have? Unprotected sex with multiple partners is never truly safe.
Unknown. There are some studies to show that viral shedding of the genital herpes virus still occurs at the site despite that fact that there is not a current outbreak. It is not well know how "contagious" this viral shedding could be. There could be risks.