You may well be right about the quote being from Einstein's 2nd wife, thank you... you reminded me that his first wife was also a gifted physicist. Cool. Einstein also said he 'had a hotline to the Old One' which I take to mean he knew how to connect to Source, and 'Listen' - him being a good, spacey Pisces, it is quite possible he got his ideas thru such intuition and inspiration.
Einstein's second wife may have said that; many people think his first wife, Mileva Maric, not only understood it, but may have written it. Some say he never produced anything nearly like the theory after they divorced.