a grown up woman should never fall so easily

I love the beginnings of relationships. Things are always so happy, and there's so much promise. Especially with this guy I've just met. I like him so much, it's sort of insane. The thing that isn't quite as good is that anytime I'm alone and I have time to think. And over analyze everything. What if he doesn't really like me? What if he doesn't want anything to do with me once he knows more about me...my secrets? How do you get over this fear of sharing yourself with someone you truly care about?
The thing that is really bothering me is that I really am a wreck when it comes to relationships...I have been hurt and had my heart broken far more times than I care to count. I just have this fear that I could lose something so wonderful...which isn't even logical thinking, because if it is that wonderful (which this truly is) and if its meant to be, it will all work out. I guess my problem is mostly patience. And I know I need to not analyze and think about things so much.
I wonder if part of it is just the culture we live in. I mean, it is sort of an unspoken rule that you shouldn't get involved too quickly, or feel to strongly too soon. The trouble is that I am naturally a very intense person, and I have a very difficult time doing anything just half-assed. Including relationships and beginnings of relationships. And my head logically knows that I am making no sense at all right now, but the rest of me, my heart and soul just cannot understand that.
This morning on my way to my doctor appointment I had the radio on and a song by UB40 came on called "Fools Rush In" (which just for the record is a great movie). Anyway, I think it sums up fairly well how I'm feeling right now. Here are the lyrics:

Wise men say, only fools rush in
But I can't help falling in love with you..

Wise men say, only fools rush in
But I can't help falling in love with you..

Shall I stay
Would it be a sin
Cause' I can't help falling in love with you...

As the river flows, Gently to the sea
Darlin so we go, somethings were meant to be..
Take my hand, take my whole life too
Cause' I can't help fallin in love with you...

As the river flows, Gently to the sea
Darlin so we know, somethings were meant to be
Take my hand, take my whole life too
Cause' I can't help fallin in love with you...

I can't help...falling in love with you
I can't help...falling in love with you
I can't help...falling in love with you...