Help with an overbearing mother..?

My boyfriend's mother is extremely overbearing and neither i nor my boyfriend know what to do. She reads texts, keeps track of all phone calls, reads internet applications (blogs, facebook, etc.), and the list goes on. She used to really like us as a couple, but now she is degrading us. She says cruel things to my boyfriend such as, "just go live with them, you care more about them than us" and she is disrespecting me and anyone affliated with me. My boyfriend has tried to tell her how I make him feel, but no matter what she doesn't want to listen or doesn't care. I have tried to talk, but she doesn't want to talk to me. what can be done?