Best thing to do is ask your boyfriend so you could be sure, never believe anything untill you know the truth or have seen it. While talking to your boyfriend about this, ask him for his phone. If he makes a big deal about it that diffidently means that he has somthing in his phone. And if he does give it to you with no problem, don't be kind and think oh he have it to me , he does trust me so I'll give the phone back. NO take the phone be smart and check through everything. Memos pictures whatsapp numbers. Just go through it. And if you don't find anything then talk to him about more and more.