I edited your question to make it into one question, instead of two.
We know about the Wright's married life from the words of Mrs. Hale. We know that they had been married 30 years, and that Minnie was a totally different person prior to get married. She used to sing, and make herself pretty clothes. After marrying Mr. Wright, Minnie Foster (now Mrs. Wright) was isolated from the rest of the world. First, we know that they moved into a hollow away from the others. We also know that they were even incommunicado, since Mr. Wright refuse to share a common phone line.
It seems like Minnie began to implode, according to Mrs. Hale, who knew her prior, because she quit singing, her clothes were shabby, and the coldness of her husband's character is evident in the lack of interest Minnie had placed in a home grown as cold as the marriage. The canary was the boiling point where Minnie snapped, obviously, and that's when she did to her husband what he did to her bird.