“I don’ see where God is OKing the begetting of children with someone other than your wife. “
We don’t whether the twins were conceived using his sperm and her egg. That would mean that the children were “begotten” with his own wife, her uterus just couldn’t gestate them.
And even if it wasn’t his sperm/her egg, it doesn’t matter.
Women having children without having the father involved in the child’s life is wrong. But that doesn’t negate the benefit of modern reproductive technology for married infertile couples.