In most open relationships I know of, the couple lives together. They either "play" together or they play together and seperately. They also make it clear that they are in love with their other half it is just that they like to have sex outside of the relationship at times. A lot of them also share their experiences outside of the relationship with each other. I was actually with a man in an open relationship and the 3 of us have become friends over the years. Me and that person no longer sleep together though.
Some people find it adds some spice to their relationship and some think it actually keeps their relationship together. Sometimes it is just the sex they want outside of the relationship and not the emotional side.
In my first relationship we weren't "open" but we did play around outside of it a few times. At this point, and actually for a long time now, I don't think I could be in one.
Because it's all about me! :)
Just give the world Love. - S. Wonder