When my soon-to-be told me he would fight me for primary custody of our school-aged children, (although I was a stay-at-home mom at the time and he owned a business that required 7-day-a-week attention) I knew things were not going to go smoothly. It turned out fine in the end, and he didn't follow through on his threat, but along the way enough hurtful things were said and done to rock me to my foundation and make me wonder how it could have been that this person had once been my partner in life.

Not all divorces are rancorous, but, of necessity, they all involve breaking up a team. What were once mutual life goals get divided into individual pursuits. You'll hear lots of advice that you should keep it respectful, and you should. But hurt feelings, abandonment and control issues and all the other things that divorce stir up can push you in the direction of bitterness.

How do you know if you're bitter? First, think about your ex. What is the first thing you feel? Be honest. If you're hurt, disappointed, and recall the latest nasty thing he said or did, you are at risk of getting bitter.

So what's wrong at being angry and bitter at someone who has treated you badly? What if he really, really deserves it? To paraphrase the saying, resentment is like drinking poison and expecting someone else to get sick. Your bitterness will only, ultimately, affect you.

Bitterness is also a way of hanging on. I've seen couples who, years after a divorce, still mention the other partner in conversation disparagingly. Moving on means creating a whole, new vibrant life so that your ex's role in it is diminished. Even if you still share responsibility for co-parenting children, you should not be concerning yourself with what he does or what choices he makes. And you certainly shouldn't be talking about it. In a weird mirror image of love, constant negativity is a way of still giving your ex central stage in your life.

But how do you get over it? Here's what's worked for me and others:

1. Stop asking why or wishing things had turned out differently.

2. Try to understand that your ex did the best he knew how to do at the time. You wish it had been more, or different, and that's why he's your ex, but look to find compassion for his limitations instead of anger.

3. Stop the "superior" self-talk. Self-righteous thoughts like, "I was nothing but good to him and he did X" might make you feel better than him, but actually fuel your bitterness. You both did the best you could, and maybe his best wasn't up to your standards. But dwelling on his missteps keeps you attached to him and the relationship.

4. Find other things to focus on. Live well. Laugh often. Find great, positive people to hang out with. Focus on a great, big, audacious new goal for your life. Get fit.

5. Don't blame. Whether your finances are in bad shape after your divorce, your children have issues, or you have lost friends you held dear, it's tempting to blame your divorce and your ex. But responsibility for the state of your life rests with you. Yes, it sounds harsh, but if you let yourself feel it, it's also pretty empowering. Life doesn't owe you anything and neither does your ex. No one bears the responsibility for your own happiness besides yourself. The good news with that is... you can make your life into anything you want it to be.

Divorce is a bitter pill. But bitterness robs you of power and drive to get out there and build a great new life after it. So, put it down and move on.