I'm going to tell me boyfriend's ex-girlfriend that she needs to start saying hello to me when she sees me around the house.
Why? Does his ex-gf give you a lot of trouble?
Yes, she makes things difficult for me and is rude to me.
Living in the same home as your boyfriend's ex must be very difficult for everyone involved. I'm sure it makes things awkward for all parties. If you are going to live with her, then you need to be able to talk to her and communicate your feelings to her so everyone can get along.
We are all adults so maybe we can do that.
You are right, you are all adults and you should be able to talk to each other when you need to. You guys need to settle this like adults.