HELP "I have a Jealous Dog"!?

Hi, my 10 month old collie dog gets very jealous, in my household there is me, my husband and three house cats. My dog is closer to my husband then me and follows him around. However if me or my husband try to play with the cats she butts in. If my husband strokes a cat or pays them any attention she barks and tries to butt in and push the cat away, she also pounces at them and if he strokes another dog she growls and snarls at them that also goes for if a dog comes over to say hello when she is playing ball with my husband. If me and my husband are affectionate to each other she also butts in and she always begs for food, even strangers we pass if they have food in their hand! We have trained her, she is house trained, does tricks, comes to her name but we just can't seem to do anything about the jealousy thing, can anyone give me any advice on this? Thanks