One way we avoid having to deal with the difficult and painful emotions that accompany the loss of a romantic relationship is through obsessing about our previous partner. This usually takes one of two forms -- vilifying or idealizing.
When we vilify an ex, we mentally replay everything negative they ever did to us. We hyper-focus on their flaws, make interpretations about their motives, their mental health, think of them as warped and perhaps even immoral or psychopathic. This is upsetting, but vilifying an ex momentarily provides relief from the heartache that comes with loss. It also takes the focus away from what our role may have been in the demise of the union.
Alternatively when we idealize an ex, we mentally replay every positive interaction building the ex up to be something that perhaps they never were -- perfect. We imagine ourselves as worthless, unless we can be with this perfect deity. This too is painful because each time the ex is put in the golden light, we cast a dark shadow on ourselves. Idealizing, just like the act of vilifying, distracts us from the grief and from the need to accept the loss as real. Idealizing an ex gives the mind a softer focus in a world that otherwise seems to promise nothing going forward but pain and misery.
If while you manage your break up or divorce you notice yourself drifting into either of these two potential obsessions, consider that vilifying and idealizing actually prolong the grief process. Develop awareness for each time you are vilifying or idealizing your ex and redirect your attention to your own feelings about the loss. Remind yourself that vilifying or idealizing are distraction techniques that will keep you mired in regrets.
If you are going to extremes about the character of your ex, consider doing a relationship autopsy where you take a calculated, rational look at the facts of the relationship -- your role and your ex's role. I describe how to conduct a thorough relationship autopsy in my pocket guide to Breaking Up and Divorce, How to Heal and Be Comfortable Alone.
The goal of the autopsy is to think about your relationship, but in a constructive and realistic manner. After all, it's natural to at first obsess as your brain comes to terms with a new reality. The obsessing is the first stage in the brain's massive reboot as it eventually accepts the loss as real.
When you obsess, write down the facts of your role and your ex's, the good, the bad and the ugly. Write the story of what really happened so that you can healthfully grieve and eventually move on.
Without this step, of taking a cold, hard look at the reality of your relationship (not an overly positive or negative perspective) and experiencing the feelings this engenders, you will remain stuck in unproductive thinking about your partner. Examining the facts eventually liberates.
There is always a backstory to a relationship ending, and it usually tells a little about how both parties have some responsibility in what transpired. Write your relationship story. Then let yourself feel it. This will help you let go.