I don't want to get gonorrhea, what is the best prevention

Monogamy. Avoiding sexual contact with a carrier is the only war to avoid gonorrhea. The fact that someone can carry the germ in their genital tract without symptoms and pass it with every contact should be concerning. Condoms, spermacides, lotions, washes etc. May slow the bug down but you can still get it. Monogamy of both partners (treated months in the past if an issue) is the sensable way to avoid it.