My wife told me to never hit her and I slapped her and this is how she responded.......?

When me and my wife got married five years ago she told me to never hit her or it would be problems. Well this past weekend we were arguing because there was a rumor that she was cheating on me and she pushed me on the couch and I hit my head. When I got up I slapped her and she went to the ground and started crying. So I left the house and went to a friends house to play cards and cool down. It was me and like fifteen other friends at his house. About a hour later we heard a knock and said come in. My wife came in and started stripping off her clothes until she was naked. She then laid on her back and spread eagle in the middle of the living room floor with her legs wide open. The room erupted in laughter. She then said "If you think I am cheating then I will act like a cheater." I ran to the car and sped off. I was so embarrased. When I left she called my cellphone and said "you need to trust me, I have never cheated, start believing me" I shouldn't have slapped her. What should I do? Basically she made a scene because I don't trust her and she was hurt. But the embarrasment in front of my friends is unbearable. I can never face them again.