How on earth have you managed not to lose it with her by now?
You’ve said you need a strategy, but seem reluctant to do what is needed. Nobody is going to wave a magic wand for you - least of all your DH, who sounds utterly useless.
So here’s a strategy for you:
Next time she comes unannounced, you go to the door and tell her she can’t come in because it’s not convenient. Explain to her that:
- you’ve explained several times already she’s only to come over when she’s invited.
- that you’re baffled and very annoyed that she’s ignored this. It’s rude and overbearing and you’ve had enough of if. She is NOT to come unannounced again.
- if she continues to turn up when she’s not wanted she will NOT be let in, no matter how many times she rings or bangs. And by the way, this is not only extremely odd and rude behaviour, it is bullying and she needs to stop it right now.
- that if she does this more than once you will cease all further communication with her.
And stick to it, no matter what she says or does, or whether the kids want her to come in or not. They’re little and they don’t say what goes: you do. I promise you that even if they get a little upset in the moment, it will quickly pass and they won’t be scarred for life.
This is easy to sort, but for whatever reason you don’t want to do it.
If she wants to see her grandchildren, she needs to comply. And she will do if you stand firm.
You’re perfectly within your rights to assert normal adult boundaries. In fact, as the mother of children who will be modelling your behaviour and rely on you to provide a decent routine, I’d say it’s incumbent upon you.
In the nicest possible way, you need to grow a spine, Op.