It's hard to tell if you W if having an MLC. The death of your brother may have steered her in that direction. A reminder that life is so fragile can do a real number on a person. When my mom passed away my W didn't even give me a hug. When I asked she reluctanly hugged me without any feeling. If your W is having an MLC it will be harder to reach her. If she's not than you may be able to ask her forgiveness. Then ask her if she can hold off on going through with the D. Ask her if both of you can go to a marriage counselor to see if the M can be salvaged. Remind her how long you've been together and how you've gone through some good and bad times with each other.
About the accusing her of the A. If would tell one of her GF's how you unfairly accused her of having an A. If you chose the GF that's the gossiper it will get back to your W.
