I am in a simular situation, as my first 2 are from a previous marriage and XH is re married also. Leaving the XW out completely may cause problems with DSS. He lives with her, and she is a big part of HIS life. What I done was when we left the hospital with bubba, we drove past the XH house to get the other kids. They all came out to see bubba, (who stayed in the car!!)and all she could say was "gorgeous baby". We gathered the kids and left. It made the other kids happy, and the new wife actually seems better now. I think seeing the real baby softened her up!! Maybe it could work for you?? Good luck, it is tricky juggling it all and looking after other peoples feelings!!