Huddy, We all go through life transitions, i.e., 20, 30, 40, etc. The way we cope w/those transitions determines whether or not we come out the other side successfully. As to whether or not your wife is in crisis, time will tell. However, just because you don't see any odd behavior, that doesn't mean she's not doing some odd things and yes, they do tend to wear masks w/different people. Wearing masks can become very stressful and tiring because it's a lot of work to make people think you are a happy individual.
Of course, your w became moody and aggressive when the kids told her what a great time that they had had w/their dad. She's not a happy camper because of the pain and she wasn't getting the attention that she wanted and yes, all of you were having such a great time. Mlcers do not like to see us having a good time in life. They want us to be as miserable as they are.
For now, I wouldn't be concerned too much as to where she is or if she's in crisis or not. Your concern and focus will need to be on you and your children. Dig deeper for patience because you will need a lot of that in the days ahead.
Sit quietly, the answers will reveal themselves when you least expect them to. The past is gone, the present is a gift and you need to focus on today, allow the future to reveal itself when it is ready.