Dating ex husbands brother illegal
(See “Marriage and Annulment” for more on this issue.) If a couple were never really married, it follows that they have no in-laws from their marriage! The relationship between a mother-in-law and her son-in-law, or a daughter-in-law and her father-in-law, is said to be in the direct line; while brothers- and sisters-in-law (as well as nieces/nephews, cousins, and even more distant relatives) are related in the collateral line.
Affinity is calculated just like consanguinity is, in lines and degrees (cf. So what happens if a spouse dies, and the widow or widower subsequently wants to marry an in-law?
By their marriage, John has become related by affinity to the other members of the Smith family, and Susan is now related by affinity to the other Joneses.Understandably, both John and his children know her rather well.It may seem entirely natural to the entire family if John eventually marries Marie, who then can help to raise her late sister’s children.Can a widowed man marry his sister-in-law in the Church?
Let’s see what canon law has to say about this subject.
The basic concept is addressed in canon 109, which defines affinity.