Finger fucking mates wife

My then friends (man and wife) Stayed over at my brothers place one time, sleeping in he lounge. They both slept on the floor beside the couch i was sleeping on. His wife between us. While he slept my hands wandered between her legs and i finger fucked her good. Got a little carried away as her moans and body writhing about woke him at one point. To which we pretended to be asleep lol. Not sure if he did know what we did as he never mentioned it. Loved sniffing and tasting my fingers that night. Went on to have a full blown affair after that. Am i a bad person?