There are a lot of risks that pop up when you give your heart to someone completely. It's a huge gamble - you have to know that they are going to take care of it. I have found that men are fickle; you never know if they're going to take care or that most precious possession or not.
If you haven't already guessed where this is going, let me spell it out for you: breakups suck. It's one of the hardest things the heart can go through, and whatever the situation that person takes a piece of you with them every single time.
Girls that can shut down their emotions and date four guys at the same time or a bunch of guys in rapid succession are lucky. They can ward off the heartbreak that follows the words "break up". As far as I can tell they can keep their heart in one piece, not falling prey to the casualties that affect others in a similar situation.
The biggest truth about a breakup is that the piece of your heart they take with them when they leave will never forget them. It holds on to the love you have for them, the memories the two of you made, and all of the details you know about that person whether you'd like to keep them or not. That part of you stays there forever, and reminds you that it's never really over...