Also, Paul expects us to take context into consideration.
A believer married to an unbeliever (quite possible when one of an unbelieving couple comes to the Lord) will in fact be faced with a “things of the world” choice.
World generally means the unsaved, unredeemed portion of humanity in New Testament parlance. I hesitate for excellent theological reason to apply it to Christendom.
Do you not understand Paul’s statement that those who are married now will soon be the same those who aren’t married, or never married? That this is passing away?
There will be no marriage in heaven. We are to look forward to that state, as that is our permanent one. This is a temporary condition we are in now, being alive in the world, and marriage is a thing that exists only in this world. Whether you marry or not, it is only for a season, and then it will be gone. So it is very much a worldly concern.