Lord Vishnu is the spiritual brother of Parvati. According to some texts, Vishnu, Shiva, Parvati, and Lakshmi are all one and the same. Parvati considered Lord Vishnu as her elder brother and performed all the rituals in their marriage. Parvati took Lord Vishnu's help in making the Shiva Lingam. In Dvapara Yuga, Parvati was born as the daughter of Lord Krishna to protect him and punish the demon Kansa. Some more facts about Parvati and Vishnu:
Before becoming Parvati, she was a human woman named "Sati" or "Dakshayani". Sati loved and married Lord Shiva even though her father did not like her. Vishnu's mother and father are Kalarupi Sadashiv and Parashakti Durga.