The difficulty of having a wounded former spouse is in the fact that you may have children together and, thus, are forced to deal with him or her. If you don't have children together, you can simply say goodbye and be done. (If your former spouse is not toxic, maybe you want to stay friends, but that is a subject for another day.)
So how do you go about dealing with a toxic former spouse who cannot seem to put the kids first, above his or her own pain? I have a few suggestions.
1. Accept the things you cannot change. I have often heard people complain about their exes' dating choices, keeping beer in the fridge, or not taking the kids to church on their weekends. They sometimes go to elaborate lengths in the attempt to control what is happening during their former spouses' parent time. While the other parent's choices have real consequences for the kids, you really have no say in how your former spouse uses his or her parent time. Unless your former spouse is exposing the kids to violent pornography or doing a drug deal in the living room right in front of them, or something of equal gravity, the courts aren't going to intervene. So, difficult as it may be, let go of trying to control what is happening at the kids' other house. Let go of the need to tell your former spouse who he or she can date or how he or she should live to be an example to the children. Instead, spend your energy on the things you have control over--including what happens during your own parent time. If necessary, let your kids just see the contrast.
2. Set firm boundaries. I recently watched as a mid-single woman received a phone call from an irate former spouse. She first tried to explain what had happened, but her former husband kept interrupting and speaking rudely. So she said, "did you call me up just to scold me?" As he got even more upset, she calmly said, "yeah, we don't need to do that," and hung up the phone. You may be used to trying to calm or placate your former husband or wife, and that habit may be hard to break. Keep in mind that, now that you are divorced, you don't need to do that anymore. If your former gets upset on a phone call, hang up. Tell him or her to call back later when they are calm. If a toxic former is at your home, don't allow them to come inside. If they become abusive, close and lock the door. If necessary, call the police. Ask your former spouse not to come by your home without calling first and refuse to answer the door if that boundary is violated. Insist that your former spouse knock rather than just walk into the home. That may be difficult for a former spouse that is used to living in that home; but he or she has no more right to simply walk in than a stranger. It is now your space and not your former spouse's. If your former will not observe these rules, install deadbolt locks and an alarm system, and call the police if these measures fail. You may need to set up custody exchanges for a neutral and public place to avoid ugly encounters. Boundaries are essential to dealing with toxic people.
3. Keep it about the kids. Often, a former spouse becomes toxic because they feel like the victim of an unwanted divorce--or an abusive marriage. How they choose to see that is no longer your business. When these kinds of charges are hurled at you, it is common to want to defend yourself. Resist that urge. Rehashing the reasons for your divorce is not helping anyone. If you could have convinced your former spouse of your point of view, you wouldn't be divorced. Simply take that kind of discussion off the table. If your former spouse starts to move the conversation into discussion of your former relationship, resentments, issues between the two of you, or painful things in your former marriage, calmly say, "That's in the past. We are divorced now and the only reason we talk is because of the kids. We don't need to talk about our personal issues with each other anymore." If your former spouse gets upset with this kind of statement, simply cut off the conversation and go back to your life.
4. Don't use the kids as a go-between. Some people don't want to deal with the toxic former spouse, so they triangulate the kids as spies or messengers. Don't involve the kids in adult business. Don't ask them to choose sides. If you find out that your former spouse is using the kids to punish you or teaching them to hate you, keep good notes of anything you learn. Calmly tell your former spouse that you are keeping records of this behavior and, if necessary, you will go before the judge and reveal it. By the way, I don't care how much money or power your former spouse has. He or she does not want to go in front of the judge and have to explain this kind of abhorrent conduct. He or she will try to get you to lose it and appear crazy to the judge. Don't take the bait in court or anywhere else. Above everything else, resolve to stay calm no matter what.
5. Create a good support system. During your marriage, you may have been used to interacting mainly with your spouse. Cultivate good relationships with family or same-sex friends who will be there for you and help you stay strong if difficulties arise. Abusive people like to isolate their victims. Don't allow yourself to be isolated.