Tchaikovsky's relationships with young boys
Tchaikovsky's relationships with the young boys such as Eduard Zak and [Vladimir/"Bob"] Davidov may have unbalanced them later in life - a not uncommon outcome when children have had sexual relations with adults. Indeed, Tchaikovsky himself harbored concerns in the case of Zak, the fifteen-year-old Conservatory student who in 1869 presumably inspired the love-theme in Romeo and Juliet, and who committed suicide four years later. as late as 1887, Tchaikovsky was still anguished about his role in Zak's suicide, confiding to his diary: "My God! No matter what they told me at the time, and how I have since tried to console myself, my guilt about him is unbearable." [Holden, Tchaikovsky, p. 271] It is noteworthy that the other great love of Tchaikovsky's life, his nephew Bob, with whom the composer was involved from an early age, ahot himself in 1906, aged only thirty-four.
source: From the book 'Tchaikovsky: Symphony No. 6 (Pathétique)' by Timothy L. Jackson; books.google.ae/books?id=9YZgJW1u9vYC&printsec=frontcover#v=onepage&q&f=false; Cambridge University Press; Book from 1999