<human>: Give me the gist of the text in a nutshell

I have been with him for 2 years, it will be 3 in January. I also was in a 5 year relationship before him from the age of 15 to 20. I met my current bf a month after the break-up and started dating him. However, I no longer want to be with him.

I have never been alone. I want it, but at the same time I am terrified of it. 

How can I break-up with him and not hurt him? What can I tell him? I feel like I'm being selfish. Part of me thinks I should just stay in it because it works fine and I don't want to hurt him. These feelings suck. :(
<bot>: I'm comfortable but not happy in  a relationship. How do I break-up with him and not hurt him?