[It all feels like it's come so right out of the blue that he can't even think how to respond, which means he's acting on instinct, which means he's getting defensive and saying things in ways he might not say them otherwise. (Although, this being Jack, it might not actually be that different. He's not the most tactful person, after all.)
Even so, he tries.]
Martha, look. I know it's sudden, a lot to get your head around, but it's the only way, the rules being what they are! I'm sorry you're upset but really I do think you're taking this a lot more personally than it's meant!