How does loss trigger love?

Natasha
For instance when you breakup with your boyfriend. I heard they won't understand until you leave, that they won't realize what they had until it is gone. I just broke up with my boyfriend of seven months for disrespecting me. He was drunk and he went off on me. I asked his sister if he'll feel anything when I'm gone though he claims he doesn't care. His sister explained, when he sobers up I guarantee you he will feel really bad... he might try to text you, to call you but you need to realize that you deserve better and just let it go to voicemail and ignore him.  I just wanted him to know I truly cared, I want him to miss me being there, refusing to give up on him even when he's hurt me so much. What are the chances of him missing me when I'm gone? 
The night before the fight, his sister, him and I were talking about his past relationships and how I've lasted the longest, I was his longest relationship. He's dumped all his past girlfriends, never being dumped. He said I have something about me the other girls never had. I left him yesterday.