In some cultures, some jealousy of the husband's family members may be that they are feeling like they have to compete with then or are feeling judged by them.
In other cultures jealousy of this sort is not common.
Hera
She was a very jealous and vengeful goddess so she didn't take it very well. She often tried to prevent the births of Zeus's lovers' children or, if this failed, she would put obstacles in their paths.
Because we often see her jealous when Zeus is off with another women
In Greek mythology, Psyche is often depicted with her two sisters, who are usually portrayed as jealous and malicious towards her. Their names are usually given as Hedone (Pleasure) and Aletheia (Truth), representing the forces that Psyche must navigate on her journey to find true love with Eros.
Hera is the Goddess of marriage so she would be jealous of her husband Zeus's affairs.
A jealous significant is person that is jealous of his/her significant other. For example, a divorced man's new girlfriend may be jealous of the divorced man's former wife because he still thinks of her, or talks about her often.
Hera was the Greek goddess of women and marriage. She was the wife and one of three sisters of Zeus, the "king" of the gods and thus was the queen. She was a jealous and vengeful goddess, often against Zeus's lovers and their offspring. Her main symbol was the peacock.
It because they think no one is good enough for their loved one ... no one is better than another and its all about maturity soon if she really loves her brother she will cut it out and grow up or the other way around its not about sex its about piece of mind
Sisters are evil because that's how they are. Especially older sisters! My older sister lies to my mother and gets me in trouble in order for her not to get into trouble. She is so evil and caniving! But you just have to get used to them being who they are.
Hera the goddess of marriage.
Often, siblings are jealous of each other, because a parent appears to show more attention to one and not the other.
In a traditional marriage dynamic, wives are expected to be loyal and devoted to their husbands. This loyalty and devotion are often described as "cleaving" to their husbands.