I want out.

alright. here's my dillemma.

Me and my gf [who shall remain nameless..[[idk why]] ] have been going out for about..ooo..1 1/2 years.?
somewhere around there.
But yeah..
I like her. I used to Love her. But things have changed. I really really want to break up, but its not that simple. I actually broke up with her about 5 months ago, boy, was that a mistake!
I was happy after that, i felt back to myself. But she was terrible. She started hurting herself, and...left me stuff like about how she wanted to die for me..and yeah.
Heads up here, this is my first relationship, so i have no idea how this is supposed to work.
But yeah, I was enjoying being back to just myself. But some nights, when she talked to me, i seriously thought she was going to do something stupid, like, real stupid.
I like her. I really care for her. alot.
But she's way into a much more serious relationship than i am. I want to be in one, but she wants to be all over and wants to have a conversation about how much we love each other every second of the day. And i get so sick and tired of it. But if i tell her this, she gets...extremely depressed. I want to break up, but i still want to be friends with her. But when we broke up, she couldn't even talk to me, cause, [she says] she doesn't know how. I know, im rambling now, but yeah.
Main point=I want out.
*sigh*
I just have no clue what to do now..