A few interesting things I came across:
From Galen Askton (and modified somewhat based on a suggestion in the original blog post comments):
Level 1: Acceptance. You are at least aware of the other person. You know his/her name. You have at least some sense of what your partner sees in this other person. You might have met once or twice.
Level 2: Acquaintance. You hang out now and then (maybe once a month) and have talked somewhat with your metamour. You have certain things in common. You have a general trust and you understand what your partner sees in this person.
Level 3: Friendship. You hang out a lot (a few times a week) and have talked extensively. You consider the metamour to be a good friend.
Level 4: Integration. You are extremely close with and emotionally intimate with your metamour. You are part of a triad or other tight intimate network. You share almost everything with this 3rd person. The metamour has become part of the family in many ways.
Level 5: Meta-"morphosis". Your metamour has become your own lover, and is no longer technically your metamour.
To be sure, the connections between any two metamours is complex and certainly not "digital" like this. Still, I think these terms can help.
Also, I would stress that this is not meant to suggest that any level is somehow more moral or better than any other. For example, if you have a good friendship with a metamour but have no romantic interest in him/her, it doesn't make sense to think this is somehow a failing. On the other hand, it's my own opinion that only reaching the "acceptance" level can be dangerous. It could be hard to trust a metamour's intentions or otherwise be sympathetic to his/her perspective.
As for me, I have to say that I think I could do levels 2 and 3 alright, but that levels 4 and 5 appeal to me the most. Having a metamour who was a close, intimate friend or a NSSO (non-sexual significant other) would be emotionally fulfilling and wonderful for me, even if the metamour never became my own lover.
"Polyfulcrum" at Journals of a Polyamorous Triad writes about Breaking Up with a Metamour:
The past several years have seen several iterations of connection between myself and my partner's partner. We've been friends, lovers, Domme/sub, and care about the same person. One thing that has remained pretty constant has been that I've seen her as family, which isn't something I extend easily or often to anyone...
While we don't have a direct relationship with each other at this time, there is a sense of loss around this for me. I guess I am pretty attached to the ideal of sharing a bond with the people I have partners in common with, at least with one that is so close to the inner workings of our lives. She's also someone that I care for and respect, although we differ in many ways.
What does this look like? As far as practical stuff, not much. It's letting go of that sense of openness, of concern, the attempts to bring someone closer, and honor that they are perfectly content to be further away, and not involved in the "friends and family"model of poly by choice....
This, for me, seems like it would be a very hard place in which to find yourself. What if I have to "break up" with the metamour over personal differences in lifestyle, approach, or expectation, knowing that my partner would continue to be partners and lovers with this person. Ouch. Complicated.
And then this gem of an expression of gratitude for a metamour, from said metamour's partner's other partner:
Today is an awesome day!
Today is the one year anniversary between my metamour (h/t for the term to Miss Polyamory for the term.) and my partner.
It’s been one full year today since my partner met this man at her best friend’s wedding and fooled around. From these inauspicious beginnings came a deep and sudden feeling of mutual love and respect that has blossomed into a wonderful supportive relationship that has helped my partner immeasurably.
My metamour helped clear away cobwebs that had festered for years. He proved to her that she could function sexually with an actual sexual partner, he helped prevent her collapse with sheer NRE when I flew halfway around the world to get my master’s for two years in denmark. He helped her work through deep seated issues stemming from rapists and abusers in her past. He helped her work through deep-seated issues with her abusive and controlling alcoholic family.
In many ways, he has been a better partner than I have, though I hardly hold it against him. We both care deeply for my partner and we have both in our ways helped her become someone she can love at least half as much as we have loved her.
The amount she has grown with his help and the positive impact in her life can never be overstated and to that end, I encourage him to remain in her life for many years more with hers and my blessing. You are a good man, my metamour and I eagerly look forward to the day I have my partner’s permission to point you out by name.
Now stop worrying about “overstepping boundaries” with me and enjoy yourself with her. I have never once been jealous or suspicious and I would not interfere with the two of you for all the money in the world. The joy you have brought into the life of the one I love has been critical and overly welcome. You are truly family and you have earned trust and respect by the score.
Happy anniversary metamour, you’ve well earned it.
*Swoon.* The hopeless romantic in me reads this and my heart swells from the thought that I might one day have someone in my partner's life who is such a blessing to him, or someone in my life about whom my partner could feel this appreciative.
I'm not really sure how all of this is going to play out as things progress in our poly journey. In the ideal, I would love to have a metamour who is special to me, and to whom I am also a special person. I can envision situations how that might work. Of the people my partner has had any level of connection with since we began our poly journey (physical, emotional, romantic), each of the three has been different. One is a close friend I adore. One is someone he met on OKC and is talking with via messages now, who has already chatted with me some online to feel me out and make sure I'm cool with it. And the third is someone from waaaaayyyyy back when, to whom we are both extremely close, who talks to me as much as he does to my partner, and already ends phone calls to me with "I love you." So far, the universe is honoring my needs. And it's not that I think that once my partner is in a close relationship with someone that I should have that much of a say over how their relationship progresses (though I can continue to define my own relationship to the metamour), but we have decided that for now, each of us does get a pretty big say in the beginning of any relationships based on our level of emotional security with the potential metamour in question.
So universe, if you're listening, here's my request... Even as I consider my own hopes for special loves to come into my life, please let someone special come into my sweet partner's life. Let them be a safe enough person that I will not worry about my partner's heart once he shares a part of it with them. Let them see in him the same beautiful things that I do and more-- a sense of humor and purpose, a genuine love for humanity, a kindness and compassion that exceeds what is typical of people in our culture, and a gentleness that melts away my every anger, anxiety, and fear. Let me be someone who is trustworthy to them, and let them trust me enough to know that even as I love him, I also love them loving him. Let them be a friend to me, and let us be special people in each others' lives, because what a special bond it would be to share love for the same person. This or something better... <3