I know exactly how you feel. I know that the person I need in my life to make me happy is my soul mate but the problem is that he doesnt realise it yet! I have loved him secretly for over a year now and he just sees me as a friend. I know that if we were together we would be happy.
Happiness is something that comes along and hits you when you are least expecting it, not when you actually want it to happen, that is my experience.
Circumstances sometimes work against us, think its called 'sod's law', you can have something going well in your life but not be happy because there is something else missing.
Maybe fate plays a part in our lives meaning that things are the way they are for a reason, but we are unaware of it at the time.