What constitutes the impediment of affinity?

[rrochon]

An article on Catholic.com states:

Henry VIII (reigned 1509–1547) was granted a dispensation from the impediment of affinity. Today, the impediment of affinity arises between a person and his or her spouse’s direct-line relatives. For example, a widower is impeded from marrying his deceased wife’s mother, grandmother, daughter, granddaughter, etc. (CIC 1092) source].

My question is, what about a deceased wife’s sister or a deceased husband’s brother?

 

[Michelle_Arnold]

The answer is found in full in the article you cite:

Henry VIII (reigned 1509–1547) was granted a dispensation from the impediment of affinity. Today, the impediment of affinity arises between a person and his or her spouse’s direct-line relatives. For example, a widower is impeded from marrying his deceased wife’s mother, grandmother, daughter, granddaughter, etc. (CIC 1092).

In the sixteenth century, though, the impediment of affinity came about merely through intercourse (marriage was not required) and extended further than the direct line of relatives. Since it was presumed that Catherine of Aragon had intercourse with her husband, Henry’s brother, the impediment of affinity had to be dispensed before Catherine and Henry could validly marry.

In Henry VIII’s time, the impediment of affinity included a deceased spouse’s siblings. Today, it does not. The logic for the impediment was that it was seen as a hedge against adultery with those of the opposite sex with whom one had a great deal of contact. In pre-modern times, extended families often lived in much closer proximity to each other than they do today (even to the extent of sharing households). The impediment of affinity was intended to condition people to see their spouse’s siblings as their own siblings, thereby making the idea of a romantic relationship with them as repellent as incest.