Back and Forth

So me and my friend, we became friends again and basically she started to go out with my bf friend. We will tell each other what we heard about each other man. Me and my bf just got back together not too long ago. So she goes over my bf house with his friend and she tells me that he had a female over there last night with him and she stayed there all night. So I’m upset pissed off and I asked him is he fooling around with somebody and he tells me that he is not. I don’t what to do or what to think. I don’t wanna be out here looking like a fool frfr. I wanna find evidence but I haven’t found any but she tells me things so I take her word for it. I haven’t looked through his phone because I don’t check phones.

I was thinking about hiring a private investigator maybe but I think that’s a reach. Like I don’t wanna have that mad woman image and have all of this make me go crazy. I don’t know what to do