This right here is the answer. Not only will having a baby make things harder for the two of you now during your final days, but it'll also mean those early formative years of the baby's life are during the worst stages of her grief.

Being a parent is tough. Being a parent of a newborn is even tougher. Being a single parent of a newborn even tougher than that. Being a single parent of a newborn while suffering tremendous grief? I can't see that being good for her or the baby.

On the other hand, if you freeze your sperm, she has time to grieve, time to heal, decide if it's still the right decision, and then if it is, pursue it with a clearer head and heart.