To me, it hurts all the same when you get cheated on, whether she was with a man or a woman. Some people might feel differently though. I'd be more upset by the idea that she slept with another girl she had feelings for versus a random guy. I'd still feel the same if it were reversed too. If she was obviously regretful, and knew she made a mistake, and you know she still does love you, then yes, I would forgive her even if she slept with a man. I don't understand why you could forgive her cheating with another girl, but not forgive her for cheating with a man. Seems kind of absurd in my opinion, and hypocritical. Haha, again, this all depends on the individual lesbian or bisexual's perspective.