Pretty strange game and title, but it's also really good and dramatic.
I'm pretty sure the best ending should be letting go, even if it hurts, because clinging on to her will strangely make you end up in the hospital and hurt yourself. :(
Whatever Leigh represents, it's not anything good...
Normally, people would want to be nice to their partner though, right? :?
I think I remember during the "bad" ending paths, Leigh actually shows a scary yandere side besides getting angry, but she also looks hurt and sad... She's scared, angry, and sad, all mixed up in one when you tell her you don't need her anymore and want to move on with your life...
I hope the guy found some other meaning in his life if he chooses to "dump" her. :(