Sleeping on my back

Ok I can't help it. I try my best, I really do, but just before I drift off to sleep I roll onto my back & I roll back to my side & then I wake up, I'm on my back again. I'm assuming I sleep like that pretty much all night, is it really that bad? Like how do I even stop it while I'm sleeping?

I've tried putting a throw pillow behind my back, but I end up just rolling on top of it or moving so that it ends up next to me so that I still end up flat on my back.