Over at Spiritual Relationships we go through a ton of articles on spirituality, dating, relationships and life in general. I personally know three people in open relationships with a primary partner and three people who are seeing multiple people casually. It's interesting that everyone who is self-assured and self-actualized gravitates to the kinds of relationships that make them happy. They don't feel the need to be pegged into any one category. That said, we do have a primal need to have a special connection with someone, be it physiological or spiritual. Over at USAToday they had an article about how committed relationships may protect against stress.
I feel it's probably people who are aligned to their wants and desires. Imagine if you wanted to be single and carefree about the people you're seeing but instead found yourself in a committed relationship, how would that make you feel? What if you wanted to work irregular relaxed hours, and being your own boss but your situation found you working 9-5 at a menial job for someone else? We feel it's about aligning to your core and being true to yourself. Of course it's also important to have significant people in your life, and a committed partner is one with whom you can share burdens, but wouldn't it just stress you out if that's not what you wanted?
Why not have a look at the find soulmate section of our website and see how you can bring the people you want into your life.