Hello. I think my Girlfriend’s dog is envious of my “presence” around the house. Great dog and we get along, but he can cut one like the best (close to my title). Jealousy or just good competition? Should I take up eating dog bones to retain the championship belt?
Could be a setup. He might be doing that when only you are around so you can get the blame. Then girlfriend gets disgusted with you. Guess who’s in the dog house then? That’s right you. 
“Listen to my dog before you start to whine,
That side’s yours and this side’s mine,
Move it on over, rock it on over,
Move over little dog, a big old dog is movin’ in”
Hah! Years ago we had a cat who did the same thing! He disliked a friend we had at the time. Every time this friend arrived, he plunked himself down in this cat’s favorite chair. The cat would glare at the friend awhile and then jump up on his lap. The cat would sit there and purr for a few minutes, and then would let out this hellacious, foul smelling fart, meow, turn around and glare at the friend and run off down the hall. It was absolutely hilarious. The cat ONLY did this to this fella. And no, it wasn’t the friend that did the farting, it was definitely the cat!
This is from your loving girlfriend… Honey, you will always retain the “championship belt” in the flatulence department. No if’s, and’s or but’s about that fact! 
Besides, I think the dog and cats love you more than they love me. 