Couple Swapping

Hi, I’m a 36 year old married woman and my husband is 40 years old. I still remember 4 years back, we were in Goa and we got an invite for a party from a random person on road. Since it was our first time, we went to that party in the evening. We saw lot of couples were dancing and enjoying there. Therefore we felt comfortable and had lot of drinks. After some time we got invited by a couple to do swapping, initially we didn’t understand as what do they want. But my husband understood and requested me to go for it as it will be fun. We went to their place and had more drinks. Then we got swapped. I felt bad tomorrow morning but some how liked the experience so did my husband. After that instance we got into couple swapping more than 10 times. But lately I have been feeling very guilty & feeling very bad for myself. I wish we never have done it. I can’t remove those thoughts in my mind. I seriously wants to undo what happened in past.