How do i break up with my girlfriend?

Today I finally confessed to my girlfriend of 13 months how I feel and that I want to be single. I explained to her that the reason I want to break up is solely due to me wishing to be single again (I've never been that social and i always enjoyed being alone), not so I can be with other girls or for anything else. As expected when she heard this she broke down crying and saying that I can't do that to her and she'll do anything to stay with me. Upon hearing that I just couldn't carry through with it, seeing how sad that it made her. So Reddit how I do go through with this??