Swaddling & rolling over

So I've read that you should stop swaddling once baby can roll over. Mine always ends up getting his arms out of the swaddle but he sometimes gets startled awake by himself. So my question is, what do you do to help your baby stay asleep if they get startled awake if you're not supposed to keep anything else in the crib, and they're rolling over? I hope that made sense. Thanks.