How about if you said something like "Look, I can hear the pain in your voice and I HATE that you're hurting, I really do. But I'm also not going to sit here while you bash me and tell me that you've never loved me, and berate me, and I'm DAMNED sure not going to help you feel better about how your affair partner treated you. If you ever decide that you really do love me, but just aren't FEELING like it right now, and you're 100% in, I think you'll find me 100% committed to helping you in any way I can. But this 'one foot on the platform and the other foot on the train' thing just isn't working for me anymore, I'm sorry."
