If you have herpes 1/2, why is it possible to spread it to other parts of your body if your immune system already has antibodies for both viruses? does this not act as a vaccine to prevent other places? or does immunity wane and u can spread?

Herpes viruses do trigger immune system responses, including antibodies and memory cells, but when the immune system is deployed against the virus, it just hides inside of the infected nerve cells and the immune system cannot "see" them nor does the immune system try to attack the nerve cells. Thus the cycle of dormancy and reactivation. The immune system never completely clears the infection.

This is a very wise question! But it appears you misunderstanding. It is NOT possible to transmit herpes to a new body area. Indeed the existing infection acts like a vaccine and prevents it.