As I begin to slowly approach being closer in age to MILs than new Mums, I wonder what sort of metamorphosis is going to happen, to evolve me from a normal person into the psychotic, selfish, unreasonable weirdo you so often see described on here.
But then I cop myself on and realise not all MILs are like this (mine a case in point), and hope that such a transition is not in my future.
OP - your MIL is being so unreasonable, it’s unreal.
You politely, but firmly tell her that alone time won’t be happening yet, that DS needs his Mum right now, and his needs (not batshit hers - although I suggest you leave that out), are, I’m sure, all of our priority right now.
And then change the subject.
And then every time she brings it up, a simple ‘we’ve already discussed this, and the (not ‘my’) position hasn’t changed’.
Change the subject. Ad infinitum.