Baby Daddy Hiding Something?

Hey all, maybe someone here knows how to help…

So I have the same phone plan with my boyfriend/baby daddy… I wanted to check and see what the payoff amount was for my apple watch so i downloaded a detailed bill but when i did, i noticed his usage was WAYYYY higher than mine and found out i can see who he’s calling and texting…Well looks like he’s been texting and calling random out of state numbers multiple times constantly. This also makes sense as to why his boss complained he’s on his phone too much…..Anyone have any ideas as to why he’s doing that?