(((((insecurity)))))
my ex used to feel the same way. It was just that he didn't understand it and he didn't want to. In fact he used it against me many times; after a fight when I was feeling really low and teary he would tell me that I might as well just go hurt myself (and worse).
It can be so damaging to not have support from your loved one, and so lonely. You are lucky you have found such a supportive community here where ppl understand your struggle adn do not judge.
You are not selfish. As Christina said it is an addiction and a coping mechanism. It is not a choice. I do not CHOOSE to hurt myself...it is something I do NOT want to do, but it happens when things get rough.
Please take care of yourself. Good luck.