Not sure if this counts since we weren't married but, years ago, after my ex-girlfriend and I broke up, we'd still meet up to have sex when we were bored and horny. We wouldn't do it if one of us was dating someone, only when we were both single. This happened maybe 5 times over a year. The crazy part was, my ex and I never hung out again socially after we officially broke up; we only used each other for sex from that point on. And let me tell you, it was awesome. My ex and I harbored lingering resentment and bitterness towards each other but there was still a strong physical attraction, so it was like we were revenge-fucking each other.