If i'm gay, how can i prevent std's with my boyfriend?

Condoms: Sti prevention for gay & lesbian partners is the same as for heterosexual couples. First, get tested. It's always a good idea to be sure before you have sex, regardless of orientation. Second, always use condoms. Besides abstinence, barrier method like condom is the next best way to prevent STI transmission, not always successful though. Third, consider to get hpv vaccination.

Get tested: All sexually active people should be tested for STDs and HIV to know their status before they enter a new relationship. You should use barrier methods (condoms) for insertive or receptive anal intercourse until you have both been tested. If your relationship is not monogamous, you should also use condoms with your secondary partners as well.