Question: do you have to be married to be a stepdad

Answer: Yes, A stepfather is the husband of someone's mother, and not someone's biological father. A stepmother is the wife of someone's father, and not someone's biological mother. A step-grandmother is not someone's biological grandmother. A step-grandfather is not someone's biological grandfather. A step uncle is the husband of someone's parent's sister (aunt) is not the father of someone's cousin. A step aunt is the wife of someone's parent's brother (uncle) and is not mother of someone's cousin. Similarly, a stepbrother is the son of a stepparent whom one is not biologically related to. A stepsister is the daughter of a stepparent to whom one is not biologically related. A step-grandson is the grandson of someone's spouse who one is not biologically related to. A step-granddaughter is the granddaughter of someone's spouse to whom one is not biologically related. Alternatively, in Australia Under the Family Law Act 1975 (Cth) a ``stepparent'' in relation to a child, is interpreted as a person who is not a parent of the child; and is, or has been, married to or a de facto partner of, a parent of the child; and treats, or at any time while married to, or a de facto partner of, the parent treated, the child as a member of the family formed with the parent.