I never really thought about it as being "exclusive". But.....We had one situation early on that was somewhat "exclusive" because any rare chance we got, we hooked up with them instead of going out to parties or meeting others. As most have said, it didn't end well. Emotions got involved and it became too much of a "relationship" for comfort. I just think it sounds too much like dating. Not our cup of tea or why we are in this.
Some folks could be a bit exclusive just because of high profile positions. I can see that as an option with a very few partners. However, it didn't work for us at all.