The 1917 Code of Canon Law has a very interesting canon on adulterers which people should be aware of:
Canon 1129- “1. Because of the adultery of a spouse, the other spouse, the bond remaining, has the right of dissolving, even in perpetuity, the communion of life, unless he consented to the crime, or gave cause for it, or otherwise expressly or tacitly condoned it, or indeed himself committed the same crime.
2. Tacit condonation is considered [to have occurred] if the innocent spouse, after being made certain of the crime of adultery, freely engages in marital affection with the other spouse; but it is presumed unless, within six months, he expels or abandons the adulterous spouse, or makes legitimate accusation against the other.”
In other words, a spouse who continues marital affections with a spouse whom he or she knows to be committing adultery thereby condones his or her adultery and is also guilty, even if that spouse did not commit adultery. This fact, which is probably very little known but which makes perfect sense, shows us, once again, how those who fail to oppose evil become guilty of it.