I feel I have a fairly good grip on what a male MLC looks like, but I believe it's different for women--others could chime in on this. Certainly the line/desperate feeling about needing to start living her life is an MLC staple.
I read the first long entry in your sitch, but it seemed to be more about your state than your wife's (and rightly so). Some MLCers push for a divorce, others are too depressed to do more than talk about it.
The clearest indicator of whether she's in crisis would be, did she have a dysfunctional childhood which left her unable to complete the entire process of growing up during her adolescence? Was there a traumatic event--a death, a health scare--which precipitated the changes in her? Did she, fairly suddenly, begin showing symptoms of depression (while desperately masking them)?
Many of the symptoms of MLC and a run-of-the-mill affair are similar. I guess the important question is, how would it benefit you to know the answer to your question? What insight are you hoping to gain? It would be worth considering your answer in detail.
