I think I'm just going to tell him I'm not ready for commitment
Why do you not feel ready to commit?
I have a lot of issues in my life, such as problems with my self esteem, and I often feel unwanted.
It's good to be honest with your partners, and to tell them your expectations for the relationship as soon as possible.  If you are having issues, you may want to speak to a professional, as they can help you.
If feel like I'm going to hurt him and make him feel alone when I break up with him.
He might feel hurt and alone for a little bit, but it's better to be honest with him now instead of dragging it out. The longer you wait the more attached he will get.