I would bring home a mountain of cardboard boxes adn start packing... Not say a word, let my actions speak for me... he WILL ask.. and when he pursues THEN you tell him
I need to get myself and these children away from this affair to protect our family from this woman. I want my marriage, and my weddding ring will remain on my finger. I am fully committed to a marriage, but I cannot live here exposed to an affair. I CAN be a wife and a mother elsewhere in a place the OW is NOT attacking our home... I hope one day you chose to join your family and protect us from her.