Is this weird for a friendship?

So two years ago I (21f) met a close friend (26m) while studying abroad. We became good friends fast and even traveled together often while on the trip. We’ve always been really attracted to one another so we hooked up a few weeks after we met and have been doing so on and off the past two years. And it only stopped when he started dating someone, which has now ended. I’m starting to feel like maybe it’s getting to be a bit too much? I feel like it’s not normal to be friends for two years and still be “casually” sleeping with each other like we met on tinder a week ago. We don’t hang out very often and only talk maybe once a week, so maybe i’m just exaggerating the friendship? is this clearly just for sex? i just can’t help but feel that if we continue it can only really end badly. All opinions welcome.