Yet, what the dog feels is not jealousy, but anger at broken order of rang in the pack. Will it surprise you to learn that dogs are incapable of feeling jealous or envious? Canines and lupines do not have the types of biochemicals, which produce the feelings, we associate with jealousy and envy. However, an angry dog is an unhappy dog, no matter what caused the anger. If you have a "jealous" dog, what you do have, is a dog, who has come to consider him/herself the leader of the pack (read: household). When you bring a new person or new animal into the pack, the dog feels that his/her rights as leader are being violated - and gets angry, though not angry at the new person/animal, rather angry with you, for not "asking permission first." Giving the dog a treat sends the dog-signal that the dog is, indeed, your leader. If you get angry with the dog, he/she will loose trust in you. A "jealous" dog is also liable to be disobedient, go to the bathroom indoors, and help him/herself to food off the table. So how did all this come about? Dogs, in general, are pack-animals, and must have a firm and fair leader. If they don't have that, they feel insecure, then instinct takes over, and the dog tries his/her best to be just such a firm and fair leader. Usually without success: There are too many things and situations in people-world that a dog cannot comprehend nor deal with without adequate (people-)guidance. A good way of establishing yourself as a firm and fair leader is through enticement and positive reinforcement. To achieve this, you will need to understand canine nature and instincts, which is not difficult to learn. Dogs, like most species, will give the same signals of communication to people and other types of animals as they would to other dogs. They take it for granted that you understand what they are "saying" and they expect you to send similar signals to them in return. An example of how easily misunderstandings can happen: In many households, the dog gets fed before the people sit down to eat, as it is most convenient that way. This sends an unfortunate signal to the dog: In dog-world, the leader decides who eats what, when & where - and the leader always eats first! If the person does not understand what the dog is "saying", then the dog gets confused, which can quickly lead to severe misunderstandings, like leadership-issues, resulting in your dog becoming so frustrated, that he/she becomes aggressive. Therefore, it remains for the person, with his/her superior intelligence and imagination, to understand and respect what dogs are all about. That way, you can have a dog, who trusts you, looks to you for leadership, and obeys you because he/she wants to. Reference Link: http://pantherakumara.tripod.com/id10.html

Explain to the dog that you want an "open marriage" and each of you can have relationships "outside the pack." Explain that it's the thing to do nowadays and that, if Sarah Palin's daughter can do it, so can you.