BF problem!

Nichole • My name is Nikki. I`m 16 years old. I like pizza more than I like most people.
I've been told by a very trusted source (whom I shall leave anonymous) that my boyfriend has asked a girl for nudes recently, but he swore up and down that he would never do such a thing. My source is like family to me, so I have no reason not to trust them, but I also have trust in my boyfriend. I solved the problem by talking to him and giving him the benefit of the doubt, but I'm not sure what I should do if I hear about him doing something like this again, or something worse. Should I break up with him the next time I hear about something like this, or continue to give him the benefit of the doubt until a situation arises where he either admits to it or I get proof of it?