Okay, this one might not be specifically poly focused but I think it still applies.
One of the things I enjoy most about polyamory is the fact you don't have to end one relationship to have another, as with serial monogamy. You can add to your poly 'family' as you see fit to the point of saturation (polysaturated), and even beyond. Though adding new partners when already polysaturated seems counterproductive to me.
Relationships can and often do change. Lovers become friends and vice versa. Deep loving relationships become more casual, and a fling may turn into a deeply committed relationship. The variations and changes are a big part of what keeps life, and moreso polyamory, interesting.
This is also where the quicksand hides.
You see, people forget that sometimes ending a relationship is a good thing. After all, if you are poly and can engage in multiple relationships, why do you *need* to end one? There are actually some good reasons why. A relationship past the expiration date, or that is damaging to both people, or damaging to those around the relationship, or requires more work than it contains pleasure, are all good examples of relationships that should probably end.
Now, for those who visit here frequently you know I'm a strong advocate for relationship renegotiation. I rarely end relationships if possible, prefering to renegotiate and redefine an existing relationship in a way that again brings satisfaction and happiness to both (or more) parties. But I'm writing this article because I'm a realist and sometimes there does need to be a definitive end to a relationship without continuation in another form.
Another quicksand pit exists within the other person. There are people out there who will grasp at any straw of hope that they can regain the relationship they once had. Unfortunately, that hope is usually based on the giddy energy that existed when the relationship was brand new, or upon misconceptions about the ability to change the other person.
In either of the situations outlined, an unhealthy relationship or one in which one person holds out hope for something that can no longer exist, I recommend a definitive end to the relationship. Now, I'm not saying you can't possibly be friends or co-exist socially within a small community. It is quite possible something can be salvaged from the relationship. But that doesn't change the need for a concrete ending to the romantic, emotional, and/or physical aspects of the relationship.
If you have tried, in good faith, to renegotiate a troubled relationship and find things still aren't going well it may be time to end negotiations and the relationship. To continue trying to make a relationship work that is unhealthy may actually cause more damage.
The same is true, in my opinion, when you are engaged with a person who holds onto hope that a relationship can return to a previous form. Someone holding onto such hope can do some strange things such as becoming emotionally unavailable intentionally (waiting), or even accepting behavior from their partner they normally wouldn't. Obviously an unhealthy situation.
My suggestion to you today is to realize when a relationship should end, it should truly end. Don't leave false hopes hanging out in the wind for the other person. This seems to be particularly challenging for males, likely due to societal conditioning that they "Don't hurt girls!". Additionally, don't struggle beyond reason to retain a relationship that is dying. Addressing things early on may leave room for friendship or more but, letting things deteriorate to the point you both are angry or hate each other will probably not even leave you with a friendship.