I'm sure the truth will come out once I'm in private conversations with my parents. But it's really important for me that my parents don't disown my wife because of this. They need to be civil towards her in order to maintain a relationship with their grandchildren.
It is very unfair to your parents to have your WW with you when you break the news. I've been in those shoes, more than once, and parents need to be alone with their adult child when first hearing of this news.
To not expect some type of reaction from either of your parents, much less in front of the one who is causing this pain for their adult child and grandchildren.......is unrealistic of you, IMHO.
Maybe your parents loved your W, but they are not in-love with her. They have a right to their own emotions. If your child was suffering at the hands of another person.....how would you feel? You will always take priority in the heart of your parents. No matter how old a person gets, it still hurts the parent to see their child in pain.
They may be very graceful, and suppress dismay over this announcement, IDK. Having privacy to ask you questions and to absorb this information is important. I just think you are being very unfair to them by having your WW there. It's also unfair to say they need to be civil towards her in order to maintain a relationship with their grandchildren. Is that your threat, or your WW's?
It is not about what you feel should work in your M. It is about doing the work that gets the right results. Do what works!