[elfchief]

In the vast majority of cases, a relationship that is broken with two participants is going to be broken with more than two participants. People don't suddenly become less obnoxious, more mature, less possessive, just because there's someone else around. If anything, existing problems tend to get rather amplified with the addition of more people.

The main case where this isn't true as much is when a relationship is otherwise good, but there are specific things that are missing -- there's not conflict, just things missing. For example, if one person in a couple enjoys BDSM and the other doesn't, adding someone that can fulfill that desire can be quite helpful.

There's always exceptions, of course, but that seems to be the way things generally work out.

[archevel]

> People don't suddenly become less obnoxious, more mature, less possessive, just because there's someone else around.

In my experience the opposite is true people DO become more mature in the presence of others. In general people tend to take a breath and try not to lose face by becoming upset in most social contexts. Also a third party can mediate conflicts, couples therapy comes to mind. Sure that's not the same thing as romantic involvment, but I can imagine conflicts deescalating just by having a third person around who can see both sides or take side or point out that the arguing parties are both behaving as idiots.