There's nothing wrong with you in that way. It can sure be a very difficult thing to change something so drastic in your life even if you know it's for the best.
Best thing I would tell you is keep in mind that you're doing this because it's what's for the best. The relationship is harming you and it's not making him any better. You know this or you wouldn't be considering the break up. If you need more, call up someone who could help you like a friend. I hope this helps you.