Sorry it's another MIL post! A long one sorry but i need advice.
Basically i want to cut my MIL out of my life for good, it all came to head this week over Christmas of course 
She's always been difficult from day one. A few years ago her and DP got into an argument and she cut him out of her life for nearly a year! She called him a disappointment and said she wanted nothing more to do with him! He forgave her and she never apologised. It was horrible for him and he was very upset about it all. Well... she's said it again. They got into an argument because she started bringing up the past (she''s in complete denial about what she said and says it never happened 
even tho we still have the messages). So DP basically said she needs to start showing him more respect and she can't speak to him the way she does especially in front of our daughter. Well she lost it and said she doesn't want anything to do with him and too have a nice life! 
Ive had enough of her, iv'e never had a good relationship with her because of what she said to DP the first time, but i put up with her. She made me feel like i was human incubator for her while i was pregnant, referring to DD as her baby and wanting to be called a name that sounded very close to mummy. She made a heartless comment about the birth, while i was still in hospital, saying that recovering from a c section isn't as bad as natural birth. She's never had to have a c section. I would never say that a c section was worse than natural birth to another woman as i don't know! She stomped all over boundaries when DD was born, undermined me and DP as parents in front of my DD. Whenever DD would start crying she would say things like "is your mummy being horrible to you" "is she not looking after you properly" Unbelievable! 
DP has said he's not speaking to her again until she apologises for everything she's done. I've said thats fine but i don't want anything to do with her. This time round she didn't just cut DP out she cut her granddaughter out. DP might allow her to walk in and out of his life with empty threats, but I'm not going to let her do that to my DD. I said I'm going to hold her to her words and she can deal with the consequences of her actions for once. DP says he supports my desision as long as his father can continue to see DD, which i am absolutely fine with. FIL knows the situation and is not getting involved. AIBU to not allow her back in DD when she comes crawling back like the last time? Sorry this was so long! 