Originally Posted by Anomaly_

The common thread is having sex with other people. Open relationships, though, ostensibly have an emotional component that swinging doesn't. Similar to what I mentioned above, open relationships are by definition flighty and lack clear structure. Ground rules are set to avoid future conflicts but there is always some level of uncertainty. In general, the type of person who gravitates toward this relationship feeds off the novelty of new people because they have trouble with intimacy. That is my hypothesis until anyone can show evidence against it.