Yes, the illusion that one is the sum of many long years of unhappiness and nothing else can be very powerful, but that's all it is, an illusion. I know people who stopped being happy when they were little kids and got to find so much happiness inside themselves as adults that they were simply amazed. So, I do not agree with you that unhappiness is a permanent state :-)
It may be that you'll need a total reorientation in life but you'll get there even without you being aware of it. All you have to do is take little steps every day for becoming happier and more stable and in time you'll find that it works. Maybe you'll have to renounce to an old way of life or learn something totally new, but there is always a way and once that you get engaged in this process, you'll be able to recognise it.
I doubt that anyone will ever be totally balanced, it's something impossible to achieve in this unbalanced and unpredictable world, but you can reach a state where you feel better about yourself and your life is back on track. You would then enjoy a love relationship so much more and if it wouldn't work out, because sometimes they simply don't or they aren't even supposed to, you'll always have your happy self to rely on. Your complete happiness should never depend on a man, or you are meant to fail and with your heart broken in pieces. Unfortunately no human being/love relationship is a reliable source for anyone's personal happiness.
It is hard for you at the moment and maybe it will still be for some time, but you're not the only one going through something like this. We're all meant to learn this lesson at some point in our lives and come out liberated, stronger, more complete and so much happier than before :-)