What is a dissolution in regards to a common marriage?

The connotations of degree of consanguinity varies by context (e.g., Canon law, Roman law, et al.). Most cultures define a degree of consanguinity below which sexual interrelationships are regarded as incestuous (the "prohibited degree of kinship"). In the Catholic Church, unwittingly marrying a closely-consanguinious blood relative is grounds for an annulment, but dispensations were granted, actually almost routinely (the Catholic Church's ban on marriage within the fourth degree of relationship (third cousins) lasted from 1550 to 1917; before that, the prohibition was to marriages between as much as seventh degree of kinship). Adoption may or may not be considered at law to create such a bond; in most Western societies, adoptive relationships are considered blood relationships for these purposes, but in others, including both Japan and ancient Rome, it was common for a couple with only daughters to adopt a son-in-law, making the marriage one between adoptive siblings.