Boundary setting (you may need to set boundaries, but you will be more effective by setting the boundaries by changing your own behavior.)
In light if this from the text itself :
pp 231 of DR
Once a person is obsessed or addicted to a particular behavior, s/he won't make the decision to change unless they have suffered some losses. They need to realize that their behavior is causing serious problems for them.
Only then will they be willing to look inward.
These are outright contradicting one another. The first is saying changing yourself is most effective in improving the marriage.
The second passage makes it quite clear that where there is "obsess[ive] or addict[ive]" behavior involved they "won't make the decision to change unless they have "suffered some losses."
Changing yourself in the case of addictive or obsessive behavior won't in this case make much difference.. according to the text.. this is an outright contradiction to what's been posted in this forum which I quoted above.
In my reading of the text a balance of consequence-rich boundary setting and sincerely looking inward to change oneself affects a better marriage. In the case where there is no obsessive or addictive activity then simply changing oneself may do the trick.
But according to the DR text once an addition or obsessive activity have gotten hold of your wayward spouse's senses you are pretty much left with no choice but to take some active measures to shake up what they are doing to ruin the marriage. If you don't shake their life up and bring some loses to their doorstep then they according to this DR text won't bat a single eyelash over it.
Clearly identifying if obsessive behaviour (alcoholism, depression, drugs, infidelity, etc) is in play.
If there is obsessive or addictive activity taking place, a different strategy according to the text is in order here.
I think it is important that this be made clear when liberal paraphrases of "working on you" etc are offered up.
According to the text, working on you when your spouse is binge drinking or gambling the household savings away isn't going to make much of a dent.