(enter silly name here)
A friend's recent advice (and test trial) was to replace an ex's real name with a ridiculous one, thus helping the ex seem much less appealing in her mind while also helping her remember why it's a good thing that she's not with him anymore (with Billy Bob, in the friend's case). A cad, a rake by any other (very ridiculous) name has less of a draw on the heart.
I'm attempting to adopt this habit.
Unfortunately, as easy as it is to pick up a bad habit, the good ones take a long, frustrating time to form.
But I'm working on it.