Md. Code, Family Law § 5–3A–29

(a) Any adult may petition a court for an adoption under this subtitle.

(b) A petitioner may petition for adoption of a child 180 days or more after a child placement agency places the child with the petitioner.

(c) (1) If a petitioner under this section is married, the petitioner’s spouse shall join in the petition unless the spouse:

(i) is separated from the petitioner under a circumstance that gives the petitioner a ground for annulment or divorce; or

(ii) is not competent to join in the petition.

(2) If the marital status of a petitioner changes before entry of a final order, the petitioner shall amend the petition accordingly.