A married person is not bound to support a spouse's children by a former marriage. However, if the person receives the spouse's children into the family and supports them, it is presumed that the person does so as a parent, and in that case, the children are not liable to the person for their support and the person is not liable to the children for their services.
Mont. Code Ann. § 40-6-217
Married person not bound for support of spouse's children by former marriage
En
Official source: Montana Code Annotated (Montana Legislature). Reproduced from public-domain Montana statutes; confirm against the official source for the current text. Not legal advice.