There was no such “proposal.”
NATO has also post a page it says corrects myths about its relationship with Russia, pointing out that the alliance has extended invitations for cooperation to Russia that have never been offered to any other non-NATO member.
The “proposal” was only a tweet by a minority party Latvian MP who claimed that Russia would be at peace with its neighbors if it was divided along ethnic lines. He did not suggest that NATO or any outside force should do this.
Read more: NATO Isn’t Planning to Break Up Russia