Cam was the same...i use to put him on his tummy to sleep during the day too- when i could keep an eye on him. Then from when he started to roll over...which he did back to tummy first from 3months, i'd find him on his tummy after most sleeps. And i find he still sleeps the same now. Josh was not such a fan of tummy sleeping, but I've found over the last week he is now also a tummy sleeper too- they take after me.