Relationships are like tea kettles. Whether a romance or collegial partnership, everyone that is in a relationship needs a way to vent off some steam at some point in the relationship. Structuring an outlet for that to occur, just as on the kettle, keeps the contents from boiling over. It is a thoughtful and prudent component of the design.
What have you done to create a release valve for your relationship? Friends can plan activities or pursue interests with varied sets of friends. Colleagues can create autonomy and work on some projects independently. Couples can take separate mini-vacations or join an organization without their partner.
Whether for a day or as an on-going pursuit, finding ways to whistle on your own is a healthy component of any relationship.