Thank you Laurie and Eva E, but I'm afraid it's all futile. Burlingame's 1000+ page tome...with all it's attendant, customary distortions of the Lincoln relationship and marriage, is being hailed as "definitive". It's apparently also won the prestigious Lincoln Prize. I think 50-100 years from now scholars will be as much influenced by Burlingame's bitter, one sided take on things as they were by Herndon's for many years.
It's all so frustrating. I keep wishing and hoping for a miracle, that the couple's lost correspondence will someday be discovered in a buried chest somewhere at Hildene...