There is a whole economic system designed around mothers and alone time – simply because we don’t get any, or when we do, someone interrupts it. 
The booze marketers know all about this, but it can become a bit of a societal issue when your only escape is in a bottle.
There are mums’ movie nights, book clubs (sponsored by wine or gin companies or accompanied by wine or gin), ladies’ nights out (more wine or gin), mothers’ journalling and reading for women, endless crafts, and innumerable  ways to manipulate your tired body. And don’t forget shopping malls.
Why? Because this is a world where you can’t shower without the door being opened five times because someone needs something and you forgot to lock it again, or it is rattled several times if you did remember to lock it and thought you might have some solitude for three minutes.Science says solitude can fix your brain, making a calmer, more creative and more pleasant being. Not the wound-up witch who will throw something if someone complains about dinner that she googled, then shopped for and executed with your health and wellness in mind.
Alone time is good for everyone. It is time to think, create, and rewire.
Alone time is the way to avoid those meltdowns that you think come out of nowhere, but have likely been building up since the last time you got some breathing space. 
A lack of solitude is the reason some mums come to work when they’re sick or feeling exhausted. Is the only way to get some peace in her little corner, where open-plan means sticking the earphones in and creating some tunnel vision?
To truly have quiet time, it takes a village. So all you people around women, listen up.

Create the escape.  As romantic as candlelit baths and massages sound, if they’re anywhere in the 5km around you, it isn’t going to work.
Tell her to go out and chill, not stay in where you can find her. 
When she’s away, don’t let things burn, in whichever way that applies. Since alone time is rarely spontaneous, because someone has to make sure all the systems are in place so the home ecosystem doesn’t collapse in that hour at Pilates, offer to help with the logistics.
Then leave. Her. Alone. To do whatever she wants to do, whether it involves running, wine, both or neither.
Listen when she says what time she will be back, and unless two extra hours have passed without contact, don’t text, WhatsApp or phone unless the world is going to end. Then let her know and she will come save you, if she feels like it.