Galatians 6:1-2

Brothers and sisters, if a person is discovered in some sin, you who are spiritual restore such a person in a spirit of gentleness. Pay close attention to yourselves, so that you are not tempted too.  Carry one another’s burdens, and in this way you will fulfill the law of Christ.

Is it my problem if a brother in Christ lives sinfully and is cheating on his wife? Yes, it is. Our relationships in Christ cannot be ruled by convenience or the fear of loss. In this scenario, I have a responsibility to confront my brother SO THAT he is restored in love. A wrong approach is for me to storm into his house and shout, "How dare you!" and publicly accuse him in front of his entire family. Unfortunately, sometimes dealing with sin comes to this because we fail each other by doing nothing when we first recognize sinful patterns, habits, and attitudes at work in one another. We must also guard against falling into temptation as well along the way. Being in God's family definitely isn't for the faint of heart. Love others as Jesus loves you, and that means bearing their burdens and restoring them in love.