Eeehmmm, Brahms never married… 1875 he wrote to the singer Georg Henschel: “I do regret sometimes that I never married. By now I would have a 10-year old boy.” A year later when he was offered the position of a music director in Düsseldorf (which he rejected), Brahms wrote to his close friend Theodor Billroth: “My principal reasons, on the other hand are also childish in nature and will have to remain unspoken. For example, the good bars in Vienna, the bad, coarse Rhenish tone (esp. in Düsseldorf) and — in Vienna one can readily remain a bachelor […] I do not wish to get married anymore.”
Adele Deutsch-Strauss was the third wife of Johann Strauss II, a close friend of Brahms. A story told in the biographies of both men is that when she approached Brahms with an autograph request, he inscribed a few measures from the Blue Danube and then wrote beneath it: “Unfortunately, NOT by Johannes Brahms”.