Chihuahua Jealousy

Question
My girlfriend has a two year old Chihuahua named Gus. She owned Gus 6 months before we met. Her and I have been together for the past year. We have patiently tried to get him comfortable with me being around, but he is always extremely jealous as he will park whenever we touch (my girlfriends parents love it :). Initially, he barked non stop when I was around, that lasted for about 6 months, for the past 3 months the bark has settled to only when my girlfriend and I touch. Gus is amazing to everyone else he meets. And when Gus and I are at home alone, he is a little better, he will let me pick him up and pet him, but he shakes a lot.
She rescued Gus, and the rescuers said that he may have been abused. Gus is a very sweet dog and I wish I could experience his sweetness. Is there anyway to solve his jealousy? Right now, we are trying just letting him stay at my place so he learns to see me as a nice owner too. But when my girlfriend comes by, he begins to act out. Any suggestions? Thank you.

Answer
Hello...lol Dog Vs Dating....it doesnt always pan out. I can reccomend you feeding Gus, offering him his toys, and his favorite treats, also walking him or playing fetch with him will teach him you are an o.k fellow and maybe he should just keep a watchful eye on you opposed to barking or snapping.