The problem with all you ditzes -- both male and female -- is that you think you OWN the other person and that person OWES you faithfulness, attention, whatever.
Your unrealistic attitudes lead to jealousy, to abuse, to murder.
If you don't like how another person is, or what they are doing -- LEAVE! (Or kick them to the curb.)
If you are the one who has been dumped, the jealous one, the stalker, the abuser, know that it's not the other person's problem that you think you can't get along without them or that you think that without them that you will never get laid again. GROW THE F** UP!