So sorry about the kidney stone - seems so unfair!!!
As for OW - I think that was excellent problem solving for H to tell her he would call from home tonight - it's great for him to make it clear you are a party to any conversations they have.
Strategy-wise? You request a DNA test after the baby is born. You and H decide BEFORE you discuss with her whether you plan to seek visitation and/or custody (don't push H if he doesn't want this, okay?). Child support comes after confirmation that this child is his. Simple.
