Should I continue to guilt my W with her actions and its affect on the family? I read that you can't guilt a person back into a relationship, and have followed that approach, but if she needs to hit rock-bottom before getting better, is guilting an MLCer a good tactic?
My personal opinion is that guilt and shame are very strong and toxic components of what people who are suffering from MLC experience. So guilting or shaming them is both destructive and may indeed drive them away (even if it works in the short term). So I guess it depends on what is your goal. If you are looking for short term fixes or to gain something it may very well work, but I suspect it causes significant long term damage to the person and probably to the chances of a restored relationship.
Sorry for the blunt opinion, and keep in mind, it is simply my observation and opinion here. But I would not touch guilt or shame as any kind of tactic in this situation.