Hi and welcome anomyness & punkexcitesme.
This is a very difficult one. And you are not the only person posting who is concerned about the emotions of their partner should they call it off.
I agree that ending such a relationship sounds like the best thing, but I too would be really worried if such threats had been made.
This person needs help, I feel. Try to get counselling and other support ~ for both of you. You both need support at the moment.
Maybe the doctor or the church could help ~ or friends & family.
I do hope that everything works out ok.
Good luck.