How often should i get checked for stds? ?

I've only had one partner. I got tested after I lost my virginity because im just cautious, even though he was a virgin too. That was two years ago. Now I've been dating this boy for about 5 months and we want to have sex. We're both 17, I know he's clean, but should I still get tested or not? I'm on birth control and I'm allergic to latex so condoms are really out of the picture.