Sex with boyfriend

Me and my boyfriend started having sex last year and we were both virgins but at the time it hurt really bad and we’ve only done it one more time since then mainly because we have a long distance relationship. But I just want to know how to make it hurt less. We always have oral sex before hand and that is great but when it comes to actual sex I’m not sure what to do because I tell him to stop because it’s hurts uncomfortably.