Caught! Fucked with my girlfriend's husband

I was with a girlfriend and we wanted to go out for a delicious meal. When she went to take a quick shower, her husband and I came up with the idea of using the time wisely and just having a horny fuck. No sooner said than done and I had his cock in my mouth. When he rammed his cock into my wet pussy, I knew why she had always raved about him. Unfortunately, it came as it had to come... Just as he jerked off inside me, she came again and caught us. She slapped him hard across the face and I guess I need a new girlfriend now. But she really could have reacted in a more relaxed way. Or what would you have done in her place?