"You're a great person, I just don't share the same feelings as you, you deserve better, it's over and cannot be resolved, I have my reasons... " pick one... just end it. It's going to be ugly, there will be tears... and there isn't much you can do about it.
"The weakest soul, knowing its own weakness, and believing this truth that strength can only be developed by effort and practice, will, thus believing, at once begin to exert itself, and, adding effort to effort, patience to patience, and strength to strength, will never cease to develop, and will at last grow divinely strong."
- James Allen