We need to begin to think outside the socialized boundaries of our binary way of thinking about relationships. There is no reason to have separate camps of “friends” and “lovers/partners”. Personally, I want my friendships to be more like my partnerships and my partnerships to be more like my friendships. Why is it that a romantic relationships is such given the power of our emotions and our lives? When we begin a Relationship (yes, with a capital R) with a person, there is often an automatic sense of obligation, of expectation. A Relationship is not longer an interaction between individuals, it becomes a thing-in-and-of-itself. You “enter into a Relationship”, you do not have a relationship.
When I begin a friendship with someone new, there is rarely a concrete starting point. It is fluid. If I have to ask someone if they want to be my friend, I think that I should begin to address the ways in which I interact with people. True relationships are inter/actions/, they should be organic.
But we create a Relationship as a thing. And it is nurtured and carefully cared for. We spend much time talking (amongst those involved and our friends) about the Relationship, devising ever-new strategies to keep it alive and well. We nurture the Relationship more than we nurture the person(s) we are in the Relationship with. But it is no longer about us, it is about caring for this thing together. And, much like a death march, or the raising of a ever-loved, yet often-resented offspring, it is understood that it's duration is indefinite yet definite. You know that there is almost certainly an end, but you spend much of your time and energy fearing the topic. Relationships don't usually dissolve or move on, a Relationship is ended, killed. But it never goes out quietly. Afterall, if something you loved and nurtured so dearly died, wouldn't you look for blame? Someone always has to be responsible....
This is the reality of many monogamous and polyamorous relationships. Polyamory alone will not solve our problems. We need to redefine how we view our relationships entirely, not simply change the number of people involved. Fuck “boyfriends”, “girlfriends”, “partners”. I want friends. I want a plethera of different relationships, friendships. I want to be intimate with those I fuck and those I don't. I don't want to have my interactions defined by whether or not I have kissed with someone.
I have many friends. Many of whom I have been quite close, even intimate with. And my friends come and go throughout my life, as our path's cross, and as we are relevant to each other's lives. We are close at some times, and not at others. This free flowing nature of social relationships is a strength, and simply a given in our (especially transient) subculture. Why would I expect, or want, anything different, anything more static, more concrete, more obligated from my sexual relationships?
If I have a best friend, or even a close friend, and they begin to hang out with a new person what difference does that make to me? If it doesn't actively hinder my relationship with that friend why should I, through my own insecurities and emotional wonderings, allow it to affect my relationship with that person. Most people can go days, even weeks, without seeing a close friend, and not lose any sleep over it. Yet often if one doesn't talk to their partner for a day, or a week (or with the arrival of facebook and text messages, god forbid they go a few hours), they become stressed, insecure, and worried. But why? Why rely so heavily on one friendship? Is life not much richer with several close friends, rather than just one? Why is it that we only allow ourselves to “open up”, to be intimate with our sexual partners? Have we not all seen the mess that erupts when we put all of our (emotional) eggs in one person's basket? And is it not equally stressful to carry the full burden of being one person's main emotional support, all the time, and be in a physical relationship with them on top of it?
I am sorry. This is more of a rant than an answer to your questions. But the only practical tool I can offer is to really analyze your interactions and relationships with those close to you and better understand why sex and romance changes everything... try to understand why the heart ache, possessiveness, jealousy, etc seems to be the domain of the Relationships more so than the friendships, and start from there and see what changes you can make in your own life from there.