By 1857 Wagner had written the first two operas as well as Acts One and Two of "Siegfried". However, the third Act of "Siegfried" was not written until many years later, because he could see that at that time there was no suitable opera house to have these operas performed. He fell in love with a woman called Mathilde Wesendonk, whose husband was very rich. This affair led to a separation with his wife, Minna. He wrote an opera about an unhappy love affair: "Tristan und Isolde" ("Tristan and Isolde").