Helen and Martin have been married for quite a while. Martin has noticed that they are arguing quite a bit more than they used to, although Helen doesn't seem to be aware of any change. They both are aware that their exchanges are more tense than they used to be, although they still communicate about as much as they have been for quite a while. Their sexual relationship hasn't changed much and they still kiss each other when they head off to work in the morning and before they go to bed at night. Which stage of relational de-escalation are they most likely experiencing?