From mixed/blended/step families, whatever the latest term is...
If you had 3 kids, with two women, would/could you treat them any differently?
Obviously, they all have different needs depending on their ages.
But could you ignore one? While spoiling the other two?
Not see one for 18 months, but take time off work every time another gets the slightest sniffle?
Buy loads of un-needed junk for two, but not give one a single penny?
Go overboard for two at Christmas, but not even send one a card?
All kids are yours, all know you. None were the result of rape or anything bad. All were wanted.