My take on it is that the dog is her excuse to push you around emotionally. If you get rid of the dog, she will just find another reason to mistreat you and keep you walking on egg shells.
Not necessarily, if she didn't grow up with cats and dogs etc, it is highly likely she didn't realise what she was getting herself into.
My wife has little experience of living with pets at all, until we got ourselves a cat (a lovely pure breed Turkish Angora) a few years ago. We lasted 8 months before, we had to find a new home for that cat. Just as lots of people really like having pets, there are lots of people whose skin crawls when they're near them.
Absent such exposure some people don't find out they don't like pets, until they end up living with them as adults.
I will also add that despite the fact I grew up with cats, dogs and birds and have rescued domestic animals and wildlife even in recent years and still happily interact with domestic animals. Having now lived without any pets for over 20 years (excempting the cat we owned), I don't want to have any pets in any home I live in ever again.