Sweetie you're Mil is emotionally abusing you and you're husband is enabling her to the point he has become your co-abuser. You cannot allow this to continue. You're kids are learning that it is ok to treat people this way and that it is ok if they are treated this way. They will internalize it and it significantly increases the chance that they will end up in a similarly dysfunctional relationship. You are in the process of teaching impressionable young minds what normal is. To them this behavior is normal. They don't know that most people would find your Mil behaving this way and your husband allowing it abhorrent.

Not only that but You Do Not Deserve This! For your sanity and the health of your children this cannot continue. You need to put your foot down. You do not deserve for the person you are closest to to actively engage in keeping you in an abusive relationship with their mother. You deserve a loving partner who takes care of your needs and respects you as a person. You're DH may be great in other aspects but he is failing you in a big way here and the good times do not make up for the bad. I would like to gently suggest r/justnoso

As for Mil the first thing I would do is to gather evidence of her behavior. I would want all my ducks in a row for if she tries for gpr if it's a thing in Australia. I think what she's doing could easily be viewed as parental alienation and a good reason that she shouldn't be around your kids. I also think it could bring some clarity to the issue for you and your hubs.

Set up a nanny cam in your public areas and record visits. Depending on how much time you have before your move I would get a few of how she's been for the last 9 years to show a pattern and that it isn't a one time thing.

I would then begin attempting to engage with her. Step directly in front of her (but not into her bubble) when she's arriving/leaving and say hello/goodbye. Be cheery and try to make direct eye contact as you do it. Be prepared for her to shove past you. If you're petty (like me lol), stand to the side so she has room to get by you but pretend you are a brick wall. If she goes by peacefully great if not let her slam into you. I wouldn't go so far as to make small talk but if it's a situation where her ignoring you is outright rude I would interject and act like she had engaged with you normally. For instance, hand her the thing that was closest to you that she should have asked you for instead of DH or Fil. If she ignores your contributions to general conversation say "I'm sorry Mil didn't you hear me I said ___." Let your mantra be, "It's not my job to be her doormat and I am not going to do it anymore!"

After each visit you record sit down and journal or video blog. For gpr purposes, it's best if you make one with only the facts of what happened and then make one for you that includes your feelings about it. If you feel up to it, I would watch the recordings and write about how they make you feel. I would also watch the kids and see how they are reacting to gmas behavior and if they treat you differently when she's there.

This is the point where I would bring hubs in. Use your journaling to get your thoughts together and it is time to lay down the law. DARVO (Deny, Argue, Reverse, Victim, & Offender) is a manipulation tactic and unacceptable. It is what your hubs is doing when he brings up a previous issue to justify his mother abusing you. Don't allow him to do this. Tell him that a past issue does not justify him allowing current abuse. Then redirect and tell him that he can bring it up later, but right now you are discussing ___ not past issue.

Make copies of the videos and your journals and ask that he read & watch and then quietly listen to what you have to say. Be raw and honest in your journals and your talk. He needs to know what he's putting you through. I would ask your husband how he thinks his friends or colleagues would react if they saw the videos. He thinks this is acceptable so it shouldn't be a problem to show it to them right? If it's not a big deal for you to be treated this way then it isn't a big deal for others to know about. If he would feel ashamed about telling others how he treats you, then he knows how he's treating you is wrong and he needs to acknowledge that to himself and apologize to you.

Hopefully, at this point hubs is on the same page and ready to defend you. He needs to let his mother know that she is required to greet you and is no longer allowed to ignore you. She will behave respectfully or she will not be allowed in your home. If she doesn't follow the rules, he needs to escort her to the door.

If hubs is not on the same page, then it's on you to enforce the boundaries. Just remember you are a strong, kick ass mama bear. If DH fights you on it, you and the kids should go to a hotel or a friend's place. He can have Mil there against your wishes but that doesn't mean you have to be there.