My fiance's mother is being a b*tch! Lots of answers please! What do I do?

i sympathise with you. the lady is probably having a major problem of identification with particular kind of life. this is a common problem with mother in laws, they feel threatened, that their place will be taken by someone else, though it sounds funny it could be true, she must be used to recieving love and attention from her son and now she has a fear that her life will change and her place will be stolen by someone else, this fear exists in some people on the subconscious level and they dont realise what they are doing basically they have to be nade awre that though externally the situation is changing internally the love is the same, it is very difficult, but being lovingly understanding is the best way to go.