Caught in the Act Again

So last night I couldn't resist sneaking into my friend's house for some fun after our weekly couples' thing. My husband trusts me completely and always lets me out late without question, which made it easier to do what I wanted. We had this whole fantasy we were just friends with benefits outside of marriage, he’s okay with it as long as I’m discreet and it doesn't hurt anyone's feelings. But last night my friend's wife came home unexpectedly early. And well, there we all were in the living room together. She walked in and literally saw me straddling her husband on the couch. Oh my god, talk about a shock! It was so embarrassing I couldn’t even move for a second, let alone try to explain myself. Anyway after that mortifying moment, somehow things calmed down again and we all ended up talking it through like adults. His wife was upset at first but came around by the end, she said as long as everyone’s in on it from now on, they can do whatever they want together. Which is fine with me I guess...but still kind of messed up to think about honestly. What am I even doing? Married and cheating with another married couple? Who knew my life would get so complicated like this.