"Asking my opinion, testing the waters about me raising that child. Having that child with us. He's asking my opinion again. "
"she'll always be able to use that baby to suck him in"
Seeing you write about a child like that is disturbing. It is ugly.
"That child," "that baby" is H's BABY GIRL. The other "demon spawn" you mention are HIS DAUGHTER'S SIBLINGS. If you reconcile, his daughter will be your daughter. The other kids will be a very important part of her life as her siblings. She is an innocent child whom your H loves who will hopefully always be a big part of his life and get to spend at least half of her time with him.