This will make 6 kids total but his current wife is the step mom of the first 4 and she wanted 2 of her own too. Which is fair I guess and now they get both in one shot so hey
So, his first two kids are his and his previous wife's, his second two were the result of said previous wife cheating on him (we found this out a few years after they were born), and his current wife just wants a couple of her own