I changed my password to something difficult to memorise which was stored in an online password vault. The result was it took an extra 20 seconds to login, which proved to be a very effective way to stop using facebook.
I rarely use Facebook on my phone, I don't like the interface at all. Mostly I'll just use it to share a pic, and even then I'm going through Instagram to do it.
I should delete the app from my phone too. Or at least switch off all notifications and move it into a folder far away from the home screen.
I haven't logged in Facebook for months because I'm too lazy to open my password manager and copy the password.