Sofia is gone for six months. In the meantime, Harpo does some "traveling" of his own, as he tells Celie, and Celie realizes that Harpo has come to find that he's an attractive man, and that he has probably been seeing many other women during this "vacation" period from Sofia.
Although it has not been mentioned earlier, it seems understandable that women find Harpo attractive, since so many people in the novel comment upon Mr. ____'s good looks and fine features.
A friend of Harpo's named Swain begins coming by, and the two start constructing a jukejoint, or small shanty bar, attached to their shack. The bar will be out of the way of the police, as it will be hidden enough by the fields and the woods behind them. Celie asks Harpo what Sofia will think of the jukejoint, but Harpo replies that Sofia is never coming back to live with him, thus her opinion about the bar does not matter.
If Harpo cannot get Sofia to "mind" him, he will find another way to assert his authority and his independence. The bar he opens brings in a good deal of money, and helps to relaunch Shug's career. It also serves as a starting-off point (as far as singing careers go), ironically, for Squeak, Harpo's second wife, whom he also seeks to control.