When Og came back, naturally, he was enraged that his stuff had been messed with in his absence, and gave Oggette the boot.
But then, he realized he couldn't find his favorite scraper.
Dangit, where was his stash of berries?
So, Og relented and let Oggette back in in exchange for keeping the place clean and finding all his stuff she had squirrelled away.
Thus were born domestic arrangements.
One thing led to another, and little Ogs and Oggettes were swarming the place before long. When they got big enough to re-arrange the cave, Oggette made them get a cave of their own.
Oggette continued to stash Og's stuff relentlessly, especially if he looked like he might want to share the hides with the younger oggette a few caves down, and so the arrangement continued.
Shortly after that, one of the tribe who didn't want to hunt those big, nasty mammoth decided he could paint caves, too, and that is where interior decorators came from, (but that is another story...)