God wants you to be separated from the rest of the world to be His people.
When God selected Abraham He wanted Abraham to leave his country, his people and his father's household who were under idol worship and follow God’s directives.
He wants each person to be separated from the rest of the people to be part of His people. It is not separation of a household, a community or a country at a time it is a person at a time.
God wants His people to exercise a healthy separation from the rest of the world. Marriage with the rest of the world can bring the pressures of the world to your life through them.