Helen and martin, in a relationship for some time, seem to be leading more separate lives and spending less time as a couple these days. they limit their interactions and don't see each other as a best friend or relational partner. they also have begun to divide their property in terms of what belongs to each of them rather than what is collectively theirs, and they speak in terms of "you" and "me" rather than "we" and "us." the two are most likely engaged in which stage of relational de-escalation?