how does logan start to treat janie differently then when they were first married

It is significant to Janie that Logan stops talking to her in rhymes, because for Janie, rhymes are linked with love. In addition, she notices that Logan stops looking at her long black hair. Janie's hair is symbolic of who she is and her sexual identity, so the fact that Logan has stopped looking at her hair indicates that he has stopped caring about her at all.