indicating the means of achieving something

के द्वारा

English Usage: She travels by bus to work every day.

Hindi Usage: वह हर दिन काम पर बस के द्वारा जाती है।

the legally or formally recognized union of two people as partners in a relationship

दांपत्य जीवन

English Usage: They celebrated their marriage with a grand reception.

Hindi Usage: उन्होंने अपने दांपत्य जीवन को एक भव्य समारोह के साथ मनाया।