The Romanov-Swan twins

A year after Renee left, Charlie met Natasha Romanov while she had business in Seattle. Natasha And Charlie became good friends. One night they both got drunk and one thing led to another and Nat became pregnant with twins. What happens when Bella and the twins move back in with Charlie? Will Bella be the selfless person she is in the books? Or will she hate no longer being an only child?