I’m not sure if this is the proper forum for this question so please forgive me if it isn’t; but I need to clear this up for a friend asap. She is living with a man in a purely platonic roommate situation. They are neither romantically, nor sexually involved. They live together strictly to share expenses, and are friends. However, they used to be romantically involved at one time. They have not been intimate in YEARS, and neither of them has any desire to be. Is she living in a state of mortal sin? I have told her that it could be potentially dangerous, but she assures me that they have lived together in this brother/sister fashion for a long time now, and there has never been any temptation at all. I told her I’d look into it for her, as she is coming back to the church and is deeply concerned. Thanks.
If she is telling you the truth - about zero sexual contact - there is no sin involved.
In fact, those who are divorced and remarried without an annulment can return to the Sacraments if they are still living together but have zero sexual contact.
Here is the reference in the CCC - " 1650 Today there are numerous Catholics in many countries who have recourse to civil divorce and contract new civil unions.
In fidelity to the words of Jesus Christ - “Whoever divorces his wife and marries another, commits adultery against her; and if she divorces her husband and marries another, she commits adultery” the Church maintains that a new union cannot be recognized as valid, if the first marriage was. If the divorced are remarried civilly, they find themselves in a situation that objectively contravenes God’s law.
Consequently, they cannot receive Eucharistic communion as long as this situation persists. For the same reason, they cannot exercise certain ecclesial responsibilities.
Reconciliation through the sacrament of Penance can be granted only to those who have repented for having violated the sign of the covenant and of fidelity to Christ, and who are committed to living in complete continence. "
I recognize that your friend was never married, but the same principle applies.
Any sexual activity by non-married persons is a mortal sin.
Further if either party is ever tempted, they should not live together.
There is no near occasion of sin if neither party is EVER tempted.
Only the parties involved, would know their true situation. The parties involved will answer to God at judgement if they are sinning.