Questions for the Loved and the Loveless

How does one go from deeply connected "in love" to soul-crushingly desperate to escape the same lover? Is it a boundary issue and a loss of personal space? Is it a false sense of love created by a reality of co-dependency? Is it a wanted, yet hated enmeshment that becomes suffocating? Do we fear alone-ness so much that we cling to and "love" another to the point of ceasing to love ourselves? And, if it's a process and a road that we travel down to arrive at that point of disconnect, shouldn't there be a return path that allows us to rediscover the best of both our self and our lover before deciding to scrap it all in a fit of rage, heartache and depletion of the soul?
I don't have answers to these questions. Theories, perhaps. Guesses, at best. Why DO some who love one another deeply maintain lifelong commitments, and others find themselves wishing, after their relationship lies in tattered and torn pieces, they had been able to repair it even well after it's gone? Those torn-asunder relationships leaving an endless scattering of "what ifs" in their wake.
I've seen people/couples grow, change, pull away and come back together, so I know it can be done. But does it take a certain "type" of person (people) for that to occur, or is it just how the wind blows on any given day? Are we all Forrest Gumps watching that random feather float and dance along a wind?
Some ascribe to the notion that everything is in divine order. It all happens for a reason. The most faithful of which can trust in this sentiment even in the darkest of moments. For many more, we can say we feel this way only when life is "good", and things are going our way. Some dismiss this notion all together...we have free will, and therefore, WE are in control of all that comes our way. "There is no such thing as 'luck'. We create it ourselves."
My personal belief lies somewhere in a balance of these concepts. I don't fully subscribe to the idea that every breath I take and every page I turn is all part of a Master Plan. "God said put your left foot forward, now your right and turn down this street at 3:05 PM..." I do believe in lessons from experiences that help me to grow and become. I want to trust in the verse from the Bible that says God has plans to prosper me and not to harm me, but I must also say that's not always an easy one to swallow when my heart is breaking, or the car needs ANOTHER expensive repair or a good friend is suffering a terrible disease.
On the flip side, I also have seen this world be indeed round! Sometimes, it takes a while to come back, and sometimes it's a more rapid return. Based on my experiences, karma exists, and sometimes I need to duck when it comes back around like a freight train in high gear....
However, as I sit in my late 30's and keep one eye on 40, I wonder what my karmic law is that I am single still, nearly 9 years after divorce. I have had a couple of long term relationships that have started well with the promise of love and commitment, and ended tragically....tears, heartache, angry words, and all. It's never easy to let go, even if you know it's the right choice. Does our heart only get so many opportunities to love before the scar tissue becomes so tough and the soul so weak that to imagine another love is to risk falling over an abyss that one might never climb out of again should our lover leave?
In some more intimate conversations with some close friends, I've been asked all kinds of questions: Do you believe you have only one perfect match, a soul mate, and if you miss it, that's all there is? Do you believe that you can truly be happy with just one person for the rest of your life? Do you think you'll ever find love again...someone that you would want to marry, and if so, how do you know? Am I too old to find a lifetime of love? Are there any good ones out there who aren't married or gay (or married but portraying themselves as single on dating websites)?
The truth is...I don't know. I wish I did, but as I'm still single and searching myself, I just don't have those kinds of answers. My jury is currently out.