I understand there is no 'law' which states to which clan any person should or can or want to 'belong' but is there a tradition or guideline or whatever for the following scenario?

A woman marries a man. He dies. She remarries, he dies. Following the reasoning that if one is to claim a clan kinship should she claim that of her father's, her first husband, her second husband, or, as she is living with the son of the first husband, would it look more "right" for her to consider herself allied with her son's clan?

Obviously, with no law to dictate what she must or must not do, she is free to choose any or none but, setting that aside, which relationship would be considered the 'closest' clan to her?