Nadezhda von Meck
In 1876 Tchaikovsky had decided to marry.  He was then a composer aged 36.  He was gay, and this was something terrible in Russia at that time.  He was very frightened that people would find out and that he would be bullied.  So he decided to marry.  He did not care who it was he married, so long as it would make him look respectable.   The next year he found a young girl called Antonina to marry.  He told Nadezhda.  She wrote to congratulate him and told him she hoped he would be happy.  A week later, Tchaikovsky wrote to Nadezhda to ask for more money because the marriage had put him into debt.  A few weeks later he was writing again to her saying that he hated his wife.  He soon separated from her.  Writing to Nadezhda was a great support to him at this time.  It is impossible to know whether Nadezhda knew he was gay or whether that would have made a difference to her feelings.  At any rate, she continued to write that she loved him.