"A position of strength is rarely a position of growth."
I saw this in a poly forum a while back, and have been pondering the relative truthfulness of the idea. While it does seem true that adversity often ramps up the growth curve to a peak, this is also where the most trauma tends to happen, and it is advisable not to confuse trauma with growth. Nor does just surviving a challenge mean you've grown from it, it just means you're still standing. Granted, some days, that's a pretty good place to be, but it still seems to me that there needs to be a level of conscious cooperation with the circumstances, regardless of the relative strength or weakness of your position, to lead to growth.
There have been times where I've been talking with someone, and it becomes apparent that they are convinced that their relationships will grow only through adversity or conflict. This is a really dangerous place to be coming from! You're setting yourself up to discount the lessons that come from pleasure and comfort as being less important or valid than the ones that come from pain and anger. At that point, it's pretty inevitable that you'll be actively seeking out things that are uncomfortable or unhappy in the pursuit of growth.
Things happen. Good things happen, hard things happen. What you choose to do, and how you decide to move forward from a given point is where the growth can happen. Within a poly landscape, there are likely to be an above average amount of factors that may pull or push you in one direction or another. Having a strong anchor point within yourself is the first and best place to focus energy when you feel like you "need" someones attention, or that you aren't adequate in a particular relationship capacity. In order to say, "I love you.", one must first understand "I".
Once you know who you are, and have some clarity on how to nurture yourself without others, it becomes much simpler to allow intimacy, with one person, or with many, because you will never lose yourself in that process. Others may enhance your experience in life, highlight your understanding of love and pleasure, intimacy and support, but the core will always remain you.
Growth can happen in quiet moments of reflection, you can learn by watching the experiences of someone dear to you. Growth can sprout in the desert of solitude, explode in a shower of sensual energy, be reflected by a child's laughter, or be expanded by something as simple as reading a thought that had not yet occurred to you personally. See those moments when they happen, and know yourself, and you will grow.