Thanks for the question.
This issue comes up more often than you would think, and the answer isn't black and white.
It is a matter of prudential judgement.
- In some cases you cannot because it would be sending a signal that you condone behavior that deliberately violates the law of God.
- On the other hand, for the ignorant, it could be a stumbling block for them to feel judged in what seems to be a most uncharitable way, thereby turning them off to religion
so you have to assess the situation and do what you can to be a living witness to the truth and encourage them to move in the right direction.
The likelihood that they would be carrying out conjugal relations under your roof is not even remote, and yet they are ultimately responsible for their behavior, not you.
If you should feel like you are in the first category and cannot abide them staying together, you can still offer them:
- separate rooms
- a nearby motel or
- something that seems mutually acceptable
but only if you can explain the rationale for your limit.
Do all things in love and gentleness (1 Peter 3:15-16) and above all pray for the Lord to guide and bless this couple.