In criminal jurisprudence, for a man to be held guilty of murder or culpable homicide it must be established that he has preconceived/ pre-planned or premeditated killing the victim thereby forming the mens rea before he executed the action, ie actus reus.
If the prosecutor can not prove beyond every reasonable doubt that the killer had already planned to kill the deceased thereby forming the mens rea the accused will be discharged and acquitted totally for murder without punishment or discharged with a “mere slap on the wrist” or will be charged instead for manslaughter which is a crime of lesser calibre/punishment compared to murder or culpable homicide.
If a husband catches his wife having sex with another man, the husband can kill both the wife and the partner she is cheating with and the husband can go scot free or better still, he will only be charged with manslaughter instead of murder. This is what has come to be known in criminal jurisprudence as a crime of passion and it has been recognized in almost every jurisdiction around the world as a valid defence for the offence of murder.
Crime of passion as a defence for murder can only hold water in court if the husband carried out the act of killing immediately after he caught his wife having sex with another man. If he waits to do it later then the action will be premeditated and the defence that he acted in the heat of passion or in the heat of the moment will no longer be valid in court.
A crime of passion has come to be defined as a violent crime, especially homicide, in which the perpetrator commits the act against someone because of a sudden strong impulse such as anger or jealousy which was triggered by the action of the victim rather than as a premeditated crime.
The basic ingredient that distinguishes a crime of passion from murder is that the perpetrator must act instantaneously in response to what happened or what he saw that triggered the impulse hence making the act not pre-planned or premeditated.
In summary, if you do engage in having a sexual relationship with another man’s wife or with another woman’s husband, you should know that if caught in the act by the man or the woman, the wife or the husband can kill you on the spot and he or she will not be charged for murder; it will only be held in court that the killer committed a crime of passion.