It can be a painful rollar coaster ride. Just hang in there buddy.
Also, try not to feel bad about OM being nice to the kids. I know it's painful because we feel it detracts from their love for us. But it really doesn't. If your W does go through with this, you will WANT the OP to like your kids. The last thing you want is OP to dislike them... That's a nightmare for the children.
I've always believed the more people who love my kids the better for them. Not that it doesn't hurt horribly. But, in the long run you don't ever want them hurt.
I'd take the pain before I'd let my kids suffer it.
There is no arriving, ever. It is all a continual becoming.