<human>: Backstory:  I'm an INTP/J and a [Highly Sensitive Person](

I got my heart shattered pretty hard by the first person I ever loved.  We were together during a study abroad program my junior year of college and when we left things we were just going to see what happened.  She completely iced me out and didn't start talking to me again until the following Fall, and acted like little happened.  I had very little closure from the relationship and  I've only just recently realized how badly that relationship messed me up.  I think I started seeking out relationships to validate myself more than to make myself happy and grow as a person.

I've been with my current girlfriend for four years.  She's on the immature side of things which at first meshed well with my tendency to goof around and not take life too seriously.  We moved in together after two years, but after nine months I realized that I was depressed and that we were not communicating at an emotional or intellectual level.  We moved out of where we were living and for the past 9 months we've been living separately and trying to work on things.  I saw a therapist for three months until I ran out of money and for a while things were looking better, but I think I've just been avoiding the inevitable.

I now realize that while she's my best friend and that I love her, I love her as her protector and as her friend, not as her counterpart in life.  She isn't very perceptive or intuitive (another source of frustration for me) and believes things are still improving.  I fear her reaction to me breaking up with her almost as much as I dread saying the words.  

I've set deadlines for myself to finally pull the trigger a couple times now and failed.  How should I approach doing what I need to do in a way that I can keep my resolve and handle whatever she'll have to say to me?  How should I overcome any last minute anxiety?

Can you give me the gist of the text in a nutshell?
<bot>: With girl for 4 years, I love her but she's not right for me, how do I break up with my best friend when she thinks things are improving?