A peptic ulcer is usually sores on the inside of your stomach or small intestines. This is what you are talking about? Or do you have sores on your mouth? Either way, neither is a risk for HIV transmission. Kissing is not a way that people get HIV. HIV in adults is transmitted by penetrating, unprotected vaginal or anal sex or sharing IV drug needles. That is really it. Saliva and air inactivate the virus so kissing is not a means of transmission.
Peptic ulcers are nowhere near the mouth. And people don't walk around with blood in their mouth. This is an irrational concern with zero risk for infection.