Sorry to hear about the divorce thing. It sounds as if your wife is being led around by a nose ring by this new partner. I could be wrong. But regardless, there's nothing you can do about it if your wife wants to separate (other than trying to physically force her to stay which obviously isn't a good option).
You could try to have a few more conversations with your wife, in case she changes her mind. But she may have to learn by taking her own path in life.
Again, my sympathies go out to you.
Love means never having to say, "Put down that meat cleaver!"