Yes, you should turn off dividend reinvestment once you retire. Use the income stream from your dividends as spending money, and if you plan to spend more on top of that, sell shares.
At best, reinvesting dividends while selling shares just adds extra complexity for the same result. More likely, it'll result in you paying higher taxes for the same level of income, because you're reinvesting the dividend income which you've already taken the tax hit on, while also incurring capital gains for the shares you sell.