Why can't I just let this go and get over him?

These things take time. Especially if it was a long term relationship. My 3 year relationship ended March of last year, and I'm still tripping about it, but it's getting better.
Just spend time with the people that care about you; family and friends, and keep your mind off of it for awhile. Although it's okay to think about, you have to accept that it's over and you need to move on.

Besides, you're probably hanging onto the memories of fun times with him, rather than missing the person you found out he really is.

Well there's the thing itself and then there's any meaning you attach to it in your own mind.

It's like if I make a play on a girl and it falls flat: it if happens in front of my friends it might be more embarrassing to me than if I was alone. Why? Because in my mind it's not just about a girl not liking my pick up line, it's now about what my friends might think.

So this thing with your first love, maybe you are attaching meaning to it that you should not be. If he's really a jerk and it's in the past than you'd have stopped caring already. Hope you forget all about him soon! ;-)

when you give someone your heart,a piece will always be with that person,and its so hard to let go,you will never get over him you will just be missing a part of your heart

It takes time, time will heal. In the meantime, keep yourself busy.

As you said that he is a jerk, that means he is not worth of your thoughts... You will get over with that... Find somewhere "a better guy" and live happily ever after...

It is relatively easy to get over those people who have done wrong and have proven to be jerks etc. When you hate someone, it is even easier...

I got personally far worse experience as first love... I fall in love entirely with girl who was absolutely perfect... I made promise to marry her... Then... She died... "That does not only break the heart, it really tears if off from the chest...". And took few years before I went to next relationship.., which ended soon after as girls parents opposed, and third relationship.., which ended as girl, altough looked pretty, was instead really mean and wicked (real "verbal abuse") picking a fight in every opportunity... I felt greatly relieved when she left... (and as I hated her, I got over her really quickly... Actually I was really happy to get rid of her)... Now, been some years alone... I know already what kind of girl I look for.... But sometimes, while alone... I do remeber that, one girl was good & nice and worth of my love.., and another one who was mean and nasty is not even worth of my thought... I can tell you this: Love decent nice guys, and hate & despise jerks... Choose from "the good and sweet ones", not "the rotten lemons".

for now, enjoy the other things that you, love the things that you and try reinventing yourself and even pampering yourself. time can only tell when will u be able to forget him it, but the power is just within u, dont let this longing be the air that you breath. you are a wonderful person and that u deserve someone better.

Because love doesn't have to make sense.

You will when you make up your mind to do so.

I dunno.
Have you tried talking to him about it?
If that won't work then you should try conseling.
That always helps me.
Write me please?
g2g.
Bye!

I think you are young and without any life experiment if you had it, you would think that is so easy let it go. Also you can try to do another things and make more friends in the world then you will feel it is easy to go. Look and Think wider in the World many many things are waiting for us to do. Dont let it stop. Because THE WORLD CAN'T STOP!