I try to remember that person at their worst. I dwell on what was wrong with them. I give all my ex-bf's derogatory nicknames. It's really damn hard to romanticize or dwell on a guy whom I now call "Eddie Munster."
If I used this 'camoflage' tactic to deal with how I feel about my ex, I punch her in her ovaries every time I saw her - and my daughter is always present, so this is a no go for me.