Your husband has a lot of nerve. He is in a rage and is trying to force you to commit psychological murder!He needs to go with you, right now, to a couples therapist. And, the focus of the sessions need to be on talking not acting on feelings. He needs to discuss why he needs to kill off someone just because he feels angry. He needs to also talk about why he is so angry at you. Putting a gun to your head and torturing you with this ultimatum is very angry behavior. He must also come to understand why he needs to put you in the role of the executioner, so that you either kill off your kid or him. How this fits with his history must be examined.In session, you must tell him that he is allowed to be angry with you and his daughter. But, he must talk about why, not act out his feelings or trying to force you to do so.Realize that many people put their negative feelings into behavior. Withdrawing, leaving, cutting off, etc. No relationship is possible when behaviors are enacted rather than discussed. And, he needs to be told this.I would also have your husband talk about how this showdown replays a scenario from when he was young. I suspect that, in his first family, someone was forced to choose one person over another. If I am right, he was the one who felt dumped way back when by the’choice.’ And, now he is trying to rewrite history so that he is the ‘winner.’So, go to a therapist and talk all this out. Of course, you must never accept the choice. And, by all means make him see that, if he insists on sticking to his position, that he will be making the choice to lose this family. You won’t make that choice, by throwing him out. He must choose to destroy himself and the family. You won’t do it for him.I am sorry that you are going through this hell.