(1) The provisions of this Subtitle on the adoption of a child of the other spouse apply accordingly to two persons in a stable long-term form of union cohabiting in a joint household.
(2) As a rule, a stable long-term form of union within the meaning of subsection (1) is given if the persons have been cohabiting
1. for a minimum of four years or
2. as the parents of a joint child, together with the child,
in a quasi-marital form of union. As a rule, this will not be given if one of the partners is married to a third party.
(3) Where the adoptive parent is married to a third party, the adoptive parent may adopt the child of their partner only alone. The adoption requires consent by the third party. section 1749 (1) sentence 2 and 3 and (2) applies accordingly.