Need a pep talk.?

I easily get attached to a person when I speak with them and get to know them. I know the best way to not so easily get attached is to date multiple people at the same time, yet that's not how I work, I can only date one person and it takes ages for me to get over this person if it doesn't work. I am at a point where its important for me to get married and I am following the tough route of dating a person, trusting him with body mind and soul; Not going after his records or chasing him down to see if he is dating someone online - for this I should get a medal because I can access anything I want anytime I want. But its killing me that even when I give these relationships my best, it has a 90% chance of not working out, God knows why !! I am a non-ugly, brown skinned, relatively exotic person and guys would not hesitate to ask me out.

Is this a general womanish thing to do ? Or is it just me, am a sadist who knows how to waste my time and hurt myself so badly ?