I've been struggling with this very question ever since I read Judge Lowrance's book. My former partner's ruthlessly clinging to the black letter of the law to demand the highest possible child support from me, even though she earns significantly more than I do and comes from a wealthy family who routinely provides her and our daughter with financial support. She's rudely dismissive of my efforts to co-parent our child, even though I relocated from an excellent job and a starkly lower cost of living in the midwest to be closer to our daughter on the East Coast.
A first look at the outlines of our breakup might lead someone to describe me as the Initiator, and that my former partner's angry responses are the natural, expected outcome of being "left." But there are two sides to every break-up; suffice to say that my decision to end the relationship formalized what my ex-partner had begun by moving away to another state in the first place. Her own myopia (maybe it's narcissism? I hadn't thought of that angle) keeps her from admitting her shared responsibility in our break up. And that's a problem. Because her sense of self-righteousness--together with her standing as the primary custodial parent (a "right" I foolishly ceded to her not understanding the financial bind I'd place myself in)--enables her mean-spiritedness toward me. Her self-righteousness also justifies, in her mind, her "right" to claim as much money from me as the law allows. In this way, the "law" feeds her myopia because she can excuse her behavior by attributing it to "what the law says." The law therefore masks her self-absorbed aggression for what it really is.
I share those details not to carp, but to be clear about the stakes involved in my effort to be "karmic" in my divorce process. Dealing with my former partner on a weekly basis has been incredibly emotionally draining. Moreover, I stand to lose a lot, financially speaking, if I don't stand up and fight back for my rights. So I have to stay alert, sharp, and aware in our dealings with one another, despite how taxing those encounters can be. And yet, I'm dealing with someone who, for a full year now, has been unrelentingly aggressive against me. What to do?
Frankly, I wish Judge Lowrance had dealt with this hard case scenario more explicitly in her book. Alas, she didn't. So I'm cobbling my "practice" together as I go. Right now, three principles guide my action.
First, I remind myself that how I end this relationship is as important to me as the fact of doing it. I don't want to perpetuate the unhealthy dynamics that led me to end the relationship in the first place. I try to use new, healthy behaviors when relating to my former partner. So, I push myself to act differently with her to avoid the bad patterns that structured our dynamic for so long. Sometimes my new behaviors provoke her ire. I tell myself that's OK, because our "old" habits got us into trouble in the first place.
Second, beyond trying to "correct" old, bad relationship dynamics, I remind myself to act and make decisions with honesty and dignity. I don't want to stoop to the bad faith, self-absorbed tactics that my former partner and her attorney seem determined to follow. I need to know I'm doing right by myself and for my child--that I'm modeling for our daughter how to act with principle in difficult situations. She sees that, I believe. Of course her preference is that her parents never split at all(she also never wanted to move away, so she understands why I felt neglected and decided to "stay apart on my own," as she puts it). But she experiences us as loving her no matter what. That's worth my efforts to stay even-keeled throughout this process. Acting "karmically" creates the ground for my daughter's emotional safety. And it safeguards my personal integrity.
Finally, though, I do have to look out for my best interests in this process. I'll be no good to myself or to my daughter if this divorce breaks me financially, let alone spiritually.
So, I do fight back on the legal matters but I fight fair and honest. This means I don't tangle with my former partner over comparably "small stuff." Such as: irritating e-mails where she digs at me in some way, shape, or form; her egregious but not insufferable assertions of "rights" (e.g., insisting on selling our house immediately, claiming 50% of our house sale proceeds, but doing nothing at all to advance the sale process, leaving those details for me to handle alone); her resentment-filled, selective sharing of information when it comes to our daughter's schooling and social life.
Instead, I save my energy for "big stuff" issues. Like the child support. Like the legal hassles about sharing the home mortgage costs. Like my visitation rights. I "chest bump" back on these kinds of issues. When I do, I don't feel guilty or hesitant at all, because I know that I've conducted myself civilly and fairly on every possible front, in every possible way. Standing up for my rights and well-being aren't uncivil, if I take those actions in good faith.
That, to me, is what narcissists can't do: act in good faith. Narcissists don't take another's point of view into account when they make decisions or take actions. They act on their own behalf solely.
Practically speaking, then, I can't change my former partner's ways or outlook. Reflecting on it, I realize that I'd hoped that by acting civilly toward her, she would've reacted to those cues that I still respected her and that she could, in turn, act civilly towards me. That's not happened. I'm trying to accept that I can't expect it to happen. That saddens me, deeply. But I can't waste time trying to change her into a state she doesn't want for herself.
One final point: I do think that with self-absorbed types, the sooner you can resolve your legal issues the better. Get a structure in place (of visits, child support and/or alimony payments, other property/material divisions, etc) that allows the two of you to routinize your contacts. The structure can keep the self-absorption in check, I think. The disputes can function as an echo chamber or fun house mirror that indulges their tendency to focus on themselves--their needs, their wants, their hurts.
I see the difference structure makes when I consider the effects of my child visitation and support agreements: the first is in place, not the second. I think my former partner's dragging out the support issues because the haggling over the law can let her act out against me for ending the relationship. If your former partner has the financial means to do so (which mine does), s/he can afford to extend that fight to your detriment.
I've said enough. I hope this provides a useful frame for comparison. Thanks for raising this important question!