Still not understanding

There are certain kinds of love I can understand; like the love of a parent or a sibling...these are obligations...and the love for a faith or  a cause; the passion of the drive is so overwhelming that it engulfs you.
But love for another person? How can you trust someone completely!? I could never think of opening myself totally to another soul, save for my brother. I have secrets from everyone. Secrets so deep, so personal that I would never even dare utter them in silence. These are secrets so sensitive that I don't even think about them when I'm with others; not a single soul...human or otherwise can ever know them. Have you ever experienced something like that? I bet everyone has...something so personal they wouldn't trust to anyone else in fear that it may be repeated.
For me, a secret is between yourself and you. The moment you tell anyone else, it's no longer a secret...regardless of how trustworthy they are...
Okay, I just ranted way of topic here...but I just don't understand how people can so freely open themselves to pain. Why would you even want that?
I know love doesn't exist! If it does, it's brief and fleeting. If I ever get married, which is another constitution I don't believe in, it won't be for love. That's the most silliest thing I ever heard of.
That's like buying a house because you liked the colour! NO SENSE!
Such a big commitment for such a trivial reason.
No, I firmly believe that all of this is just what the media forces down our throats making us believe that fairy tales do exist! Marriages end up in divorces almost equally as they survive, which proves just how efficient marrying for love is!
So yes, I may seem cruel and heartless but facing the facts here. I am nothing, if thorough. I make every decisive calculation before pursuing a cause. From what I can gather, all this nonsense is an act of faith ...I am a Muslim because the signs have been made clear to me...I can see the reality of my religion as clear as I can see light. I know the truth of what I am being taught. But this, these are practices of mortals...people who make mistakes...how can I take that seriously?