He never keeps it unlocked I guarntee you, he even takes it with him in the bathroom when he takes a shower and if he doesn't it is in the bedroom charging but in locked position.
Sounds just like my H during his PA. He even would keep it in his pj bottom pocket when he went to bed.
PDT gave me the same advice about a wayward letting their guard down and you know what... one day H left his cell phone unlocked in the bedroom while showering. I was prepared and I found what I needed to confirm all my suspicions.
And Pearl would tell me trust my gut feelings too. And it was dead on!