I want to know the answer to the following question:
How long were Jefferson and Hemmings in a relationship?
All the background I'm provided with is that "As noted in the 2012 collaborative Smithsonian-Monticello exhibit, Slavery at Monticello: The Paradox of Liberty, Jefferson, then a widower, took Hemings as his concubine for nearly 40 years.". Is that enough to answer the question?