Mariticide is the murder of one's spouse, especially the murder of one's husband by his wife.

The act of killing one's wife is called "mariticide." It is a serious crime and is punishable by law.

Killing of one's husband: Mariticide or viricide

Killing of one's wife: Uxoricide

Following is the list of some words containing the suffix cide: avicide, germicide, insecticide, pesticide, fungicide, fratricide, patricide, matricide, sororicide, infanticide, feticide, homicide, regicide, canicide, felicide, mariticide , filicide or prolicide , genocide, femicide, vaticide, amicicide ,uxoricide etc.

You probably mean Fratricide.

Fratricide (from the Latin words frater "brother" and cida "killer," or cidum "a killing," both from caedere "to kill, to cut down") is the act of a person killing his or her brother. Related concepts are sororicide (the killing of one's sister), child murder (the killing of an unrelated child), infanticide (the killing of a child under the age of one year), filicide (the killing of one's child), patricide (the killing of one's father), matricide (the killing of one's mother), mariticide (the killing of one's husband) and uxoricide (the killing of one's wife).