Hi MR,
If she is acting like a teenager, with very few responsibilities and is very selfish, that is not a mom for your kids that you once knew. Hence, identity crisis. That is part of the mid-life crisis.
Other things that point to midlife crisis/identity is the fear of getting old. Obsessing over the body, plastic surgery, excessive excercise, eating habits change, not able to deal with everyday life easily. So they are not able to accept the fact that they are
aging and moving into a new phase of their life.
I personally do not understand it. I have read about it. See it happening with my W too.
Supposedly, men all go through some type of midlife crisis, or male menopause, called andropause. The Conway books talk about this. I have not experienced this yet at age 48. Thought about getting older about 5 years ago for about an hour or two one day.
I am too busy to think about that stuff. Maybe it will hit me sometime in the future. The books say some get through midlife without any problems. Hormone levels for Men and Women can play a big part in this. That I can believe. I guess if my hormone levels changed, I would sense something is not right. I don't think I answered your question, but it made me think of this as a response.