There's a big difference between an addiction and a bad habit. If it's a behavior you can control, chances are it's a habit. And the bad ones, however ingrained they may be, can be broken. Good luck though; it's not always easy.
There's no doubt about it, change is hard. And to change an undesired behavior you've been doing so much it's become involuntary, you have to be conscious of it. Only then can you start making good choices.
Let's say you just got dumped. Or perhaps you were the one doing the dumping. Either way, you probably developed some pretty bad habits with your ex, making it even harder than it already is to let go.