Will the church -in New Jerusalem- be separate from all other believers for eternity? Will there be 2 heavens? Thank you for considering questions from confused people like me.
All we know for sure is that during the Millennium the Church will live in the New Jerusalem while Israel and post Church Gentile believers will live on Earth. How this may change when the Millennium ends and we pass into eternity has not been made known. It’s one of those things that will be revealed to us at a future time.