What is he doing?

So I recently found my husbands old phone he no longer uses and the charger in the cupboard in our bathroom, I asked him why it was there and he just said I dunno and changed the topic. I checked it to see if anything was on it but it’s like the history keeps getting wiped out, also it’s been charged numerous times. He spends a lot of time in the bathroom right before bed and right he after he gets home from work. Any idea what he’s going? There is no SIM card in the phone so I don’t think he’s calling or texting anyone but wtf? We have 2 kids together so I’m hoping he’s not doing anything wrong.