miranda and via used to be good friends. why did heir relation ship change?

Miranda's parents had a divorce and she grew distant from Via. During the school year, Miranda seldom sees Via, and she and Ella badmouth Via behind her back because it is easier to alienate Via if they pretend that she has acted against them in some way. But Miranda and Ella are the ones who have changed; Via actually did not. Miranda remembers seeing Via's boyfriend Justin for the first time; she has a boyfriend, too, a varsity jock named Zack.