OMG! My best girlfriend's husband fucked while SHE was with me

I still can't quite believe it. Have I really just betrayed my best girlfriend Claudia? When we were out partying with the group last night, Claudia's husband put his mobile phone in my pocket. Of course, we forgot about it in the s*ff, which is why he picked it up today! And I can't even explain what happened next. When did I become such a merciless bitch?