Had you ever cheated ? ......Why ?

I thought I moved on from my ex a year after I was with my new boyfriend, but I was in a really bad spot. I thought my new boyfriend was hiding stuff from me/cheating on me, and I hardly ever saw him. I was really depressed, and I was having second thoughts on my feelings were towards my new boyfriend, because I was starting to realize that I didnt feel the same for him as I did my ex. One day, I was with my ex's sister, who was my friend, another guy, and my ex who joined us. For context, my ex is a player. He KNOWS how to get right into any girls pants, and I knew that. But... I was so stressed and sad, my head ignored all rationally and just kept saying "Just do it, you want him. If you set this up right, he will want you too." So thats exactly what I did. I set the scene up perfectly, my friend started to head to bed when I asked my ex if i could watch the movie he was going to watch, and he agreed. Everything was fine at first... until 30 minutes went by and he took the bait. I ended up falling asleep with him on the couch, and he got up early in the morning when his dad got up for work. I ended up telling my boyfriend, and he forgave me. A few years later, I ended the relationship, and I am single now. I feel so awful for what I did. But, luckily, we are still friends and he is doing really good now a days. And so am I.