Name changed as this situation is quite specific, plus I may show thread to DH to help with the discussion.....
Writing for advice from brutally honest lovely mnetters about MIL situation. Will try to keep this brief!!
DH and I have been together a long time. Have toddler DC. If I'm honest, I've never liked MIL because she is rude, tactless, has no awareness of other people's feelings or personal space (!), says horrible things to people including DH and has upset him many times over the years. Says things like "oh I didn't think you'd fit into those trousers, I thought you were too fat" for example (not said to me)
I have always been able to 'tolerate' her company at events by passing a few civil pleasantries whilst basically inside rising above her comments and not really giving a toss what she actually thinks of me.
But since I have had Pfb (who was much longed for a fought for) my indifferent tolerance has turned into a deep hatred! I can't help it! I just don't want the woman anywhere near me or my precious DC!
I started off trying to give her the benefit of the doubt. I invited her around before the baby was born to show her things we had bought, saw her at the hospital so she could hold the baby despite having a REALLY traumatic delivery and really being in NO fit state for visitors. Had her around several times in the early days and tried to include her in things like bathing the baby etc.
But on each and every occasion she has been out of line, said something offensive or just plain been horrible.
Examples: when shown baby stuff said (to a heavily pregnant woman remember!) "and can you return all this stuff if something goes wrong?" And "are you buying in any formula in case you fail horribly at breastfeeding?"
Said to me out of the blue about 6 weeks after the birth "you've lost weight, but you still have a bit of a stomach don't you"
She invades my personal space all the time when I'm holding pfb. When pfb woke up from their nap she snatched baby out of my arms and walked off with baby, despite baby screaming for a feed and my boobs leaking everywhere.
On another occasion at a family thing we walked through the door and she literally ran over, snatched baby out of my arms (I'm not exaggerating) and proceeded to pass baby around like a pass the parcel. This upset pfb a great deal who is a very clingy baby and is genuinely terrified of strangers.
Pfb also suffered terribly with reflux and screamed a lot and would not sleep. Mil advice was to put baby in cot, shut the door and just let them scream. An 8 week old baby. Seriously. She said "that's what I did with all of mine. Parents have to get their rest"
Obviously we filed this under 'bollocks' and carried on doing it our way (Dr Sears style!)
Currently we live abroad so have not seen mil for many months. Unlikely to see her again for another 18months-2 years.... But I know when we move back she will want to be around pfb (and possible siblings by then?). I just don't want her having a relationship with pfb. I don't see what positive thing she has to offer.
Last incident was just before we left and she was holding pfb. Pfb started to cry and I said please give baby back so I can settle them. She said "no I'm not giving them back" and refused! DH had to shout at her before she let go of baby.
DH does recognise that his DM can be difficult and does challenge her on her behaviour. But ultimately it makes no difference to her behaviour. DH wants to have an ongoing relationship with her but I just can't see how it will work, even going low contact. I know I will always be so tense around her, waiting for her to say something hurtful or inappropriate to pfb (have witnessed this with her other DGC....example "he's enough to put you off having children" said in front of 3 year old DGC who has later said "why does grandma hate me?")
DH just feels devastated about the idea of going NC though, as he does love her and want to have a relationship with her. He doesn't think that me and DC going to NC but him still seeing her is an option (I don't really understand why but his mind is made up on that one). He thinks it's all or nothing.
It's not immediately pressing but it does play on my mind and every time we bring it up we just argue and it never gets resolved/we never make any kind of decision. I don't even know what I want to do really. NC feels quite harsh, but on the other hand the thought of pfb being around her makes my heart shudder.
MN jury, what do I do? Have you been in a similar situation? What did you do? What can you advice?
Thank you.
Sorry it was so long after all 
Ps, I may not be able to check on replies that speedily!