I already answered this for RP on facebook, but I'll share what I posted there here too.
"I don't view commitment in the traditional sense. My heart adopts people, sometimes before rational thought; some romantically; some children; some just friends. But once that happens, those people are "mine" and I will do everything in my power to see them safe, happy, and loved. We are, as some say, fate bound to be part of each other's lives in some way or another until this life parts us."
To that extent, commitment comes from my spirit/ soul/ or whatever you want to call it. It isn't something that I can take back; comes with a fierce loyalty; and does not fade as the person's role in my life changes or distance separates us. Once I am aware that my spirit has committed to someone, I can take actions to deepen that commitment if necessary.
I am committed to a handful of people. Romantically there is Runic Wolf, Wendigo, and Pretty Lady. I also have adopted Stew (a longtime friend with occasional benefits) and his ex-girlfriend, N (who is also a longtime friend with occasional benefits), my good friend Purple, and while these are all people that I am attracted to, are my soul friends. Then there are the children who I am committed to, my son Yoda and my adopted niece, Mia. In each of these people, there was a sense of being "home" when I am with them.
I honestly couldn't tell you what makes some people worthy and some not because that is not where my commitment comes from.