Hummmmm I'm wondering if it might be useful for you to contact husband in a concerned way and without blame or anger, ask him if he plans to make the kids a distant memory. If I were going through all this I might just approach my husband with this concern and ask him if he plans to do this. I might say that OW informed me that she plans to make the kids and me a "distant memory" and if that's the case, you'd like to know now so you can prepare the kids for his absense in their lives.
Add in, you are not blaming him or angry, you would just like some clarity about this so you can prepare the kids.
There is no arriving, ever. It is all a continual becoming.