Evidence Act S. 114
Where the partners lived together for long spell as husband and wife there would be presumption in favour of wedlock. The presumption was rebuttable, but a heavy burden lies on the person who seeks to deprive the relationship of legal origin to prove that no marriage took place. Law leans in favour of legitimacy and frowns upon bastardy.
Badri Prasad v. Dy. Director of Consolidation, AIR 1978 SC 1557