SOS, poorly educated

my boyfriend is is a lot more experienced than me when it comes to sex. he's my first, but I know he's been with other girls before me. I havent asked if he gets checked regularly, but I remember, while talking about something else, that he said he hadn't gone to the doctor in years... I haven't had any rashes, discomfort or any irregular things like that but should I be worried? how do I bring up the topic? do i need to bring up the topic? how crutial is it to get checked, and how often should you? is there a high or low chance the either of us has something?