My parents have two pets: a high-strung hunting dog (a German shorthair pointer, if you're curious), and a psychotic cat with no claws who originally belonged to my sister. The dog is exuberantly, enthusiastically erratic, ninety pounds of jumping, barking, tearing around the house, freaking-out-without-warning teeth and claws that has actually injured my mother badly enough to require surgery on a morning walk. ("Oh look! A squirrel! I'm going to go chase it, oh boy oh boy!" led in very short order to a torn rotator cuff, when the dog hit the end of her leash.) The cat doesn't much cotton to people, or to anything else really, and will growl, hiss, and generally make her displeasure known when one of us naked hairy apes intrudes into her presence.
What does that have to do with polyamory? Glad you asked.
The dog doesn't much like the cat, and the cat doesn't much like the dog. Actually, that's not quite accurate. It's probably more fair to say that the dog, being carefully bred for the purpose of hunting, rather does like the cat, in much the same way she likes any prey animal, and the cat hates the dog with a fury that is scarcely comprehensible to mere humans, but it's a fury that is as impotent as it is malevolent. There's no contest between the two. If the dog were actually to get at the cat, the dog would kill the cat in very short order--game over, the end--exactly as the dog has been bred to do.
For this reason, my parents carefully segregate the dog and the cat. The cat lives in one side of the house; the dog lives in the other, and doors are closed between them.
It would only take one mistake, one accidental slip-up, for my parents to own not two pets, but one pet and one collection of bloody scraps. So they are religious about keeping the animals separated. Doors and windows are checked after every passage (the cat's domain includes the screened-in porch, which the dog is not permitted in). The habit of closing the door after every passage has become so strong that every door in the house is generally kept closed.
In some ways, this mirrors their relationship. My father lives on one side of the house; my mother lives on the other. They interact seldom and actually spend time together more rarely still. Even on vacations, they tend to go in separate directions.
Some folks in the poly community seems predicated on the same model as my parents use with their pets.
For many people, polyamory in practice seems a bit like owning a dog and a cat that don't much get along, or in some cases might even try to kill one another. Each relationship functions as a separate entity, and doors are shut between them. If Alice is dating Bob, and Alice wants to date Bill too, and Bob and Bill don't much care for one another, the solution is scheduling. Keep Bob and Bill away from one another, and it's all good.
After all, Bob and Bill aren't involved with each other, right? There's no reason that Bob and Bill have to force a friendship, or even interact with one another at all, just because they're both dating Alice, right?
That's true up to a point. Certainly no reasonable person would suggest that Bob and Bill should try to be something that they're not, or should attempt to force a connection or a friendship where none exists. that way disfunction lies. And it's not necessary in a healthy relationship for everyone to be romantically involved, or even to be best friends; poly relationships can function just fine as long as there is mutual respect and understanding amongst the people involved.
But if Bob and Bill absolutely can't get along with one another, there's something else Alice might want to think about.
Presumably, Alice has a choice. Alice can choose who she becomes romantically linked to. Alice can choose to date Bob and to date Bill, if she likes...but she can also choose not to.
At the risk of sounding cynical, it sometimes seem to me that many people in the poly community approach their relationships from a "starvation model." Connections are so rare, and the number of people who would actually want to date me so few, the reasoning seems to go, that if Bob asks me out, I have to say yes! If I don't, I may never get another chance to start a new relationship again. Best to take every opportunity that comes down the pike; best not to risk never having a new relationship ever again.
And sure, it can work, in much the way my parent's lives work--you learn to cope, you develop the reflex of shutting doors, you learn to police yourself constantly and to keep the things in your lives segregated. The habit of openness can be quashed, in time; you learn not to share things with Bill about Bob, you learn not to schedule things where Bob and Bill might interact. You develop a subconscious internal policeman, whose job it is to maintain that separation, to ensure that Bob and Bill forever occupy different spaces in your life.
Is that the kind of life you really want?
It's not necessary to try to make Bob and Bill like each other. Nor is it even possible, really. But what Alice can do is make choices. She is not obligated to date anyone who will have her; love is abundant, and she can make choices about who she invests her emotional and romantic energy in.
What Alice can do is choose the kind of life she wants. She can, if she doesn't want to become a devout follower of the Church of Closed Doors, evaluate as part of the decisions she makes what impact a potential new mate will have on her existing mates. She can say "I like Bob; I enjoy Bob's company; but I don't want to spend the rest of my life closing doors and policing my partners, so if Bob doesn't fit well in my life, I will make another choice. I can develop a friendship with Bob that honors and respects the connection between us, without being involved in a relationship with him. I can choose relationships with people who complement my life and each other's...even if they're not actually involved in romantic relationships with each other. I can build a life without doors and walls."
There are disadvantages to this approach. One may, from time to time, have to pass up the opportunity to sleep with someone one wants to sleep with. One may not be able to pursue every opportunity that presents itself. But in a world of six billion people, we have to make choices anyway; and love is abundant. There is no need to date a person who does not fit well into your life and mesh well with your existing relationships.
The benefits to a life without doors and walls are wonderful. When you choose partners who can become friends with each other, everyone benefits. One of the nicest things about polyamory for me is that when my lovers become romantically involved with other people, I can meet people who add value to my life, even though I am not romantically or sexually linked to them. Relationships chosen to complement one another, rather than relationships that have to be separated from one another, benefit everyone. When you chooses a new partner, your existing partners can be enriched by it as well.
Of course, this assumes that everyone involved is willing to make a good-faith effort to be open to new people. There are folks, it is true, who are closed to the idea of a partner dating someone new; other folks are closed to new people who are involved with a partner but not with them. And in these situations, making choices becomes difficult; you can not choose a new partner who can get along with your existing partner if your existing partner is predisposed to seeing anyone new with jealousy, hostility, or anger. In such cases, it might be beneficial to work on those issues before taking on new partners.
Wherever possible, I am an advocate of making conscious, deliberate romantic choices, and of choosing romantic partners who fit well into one's life. Doing this, I believe, is one of the keys to a happy and successful romantic life.