Perhaps the hardest thing to do is swallow your pride. Good men learn to do so. We swallow our pride when we confess sin, when we repent, and when we apologize. We also swallow our pride when we forgive.
I wonder in the end if there will not be more people lost for prideful unwillingness to repent or to forgive than for any other matter. If your pride is too big to allow you to reconcile, then your pride is a stumbling block. It could cost you your soul (Luke 13:3; Matt. 7:14-15).
God is so good to us. He will forgive us of nearly any sin. But God draws a line at continued, willful sin (Heb. 10:26). I worry for the person who refuses to repent. There comes a point when one cannot touch such a person anymore (Heb. 6:4-6). He doesn't want to hear it, and you can't get through to him/her.
I want to go to heaven, and I want all my brethren to be there. If we go, it means that we will have to let go of some of the past. Those who sin against God must give it up. Those who see their brothers and sisters truly repent need to give up their animosity and forgive. The problems come along when someone decides he/she will not give up their sin or when others decide they will not forgive.
Unity is important, but unity apart from Biblical reconciliation is not unity. It is compromise.
To say that I am willing to open my arms to a brother who willfully hangs on to an unauthorized practice may sound attractive to a postmodern world (that thinks little of truth); but that kind of friendship is hostility with God (James 4:4-5). Kindness, yes; but an embrace that endorses sin cannot be. We cannot flirt with those who have no intention of giving up their sins and take for granted the grace of Christ.
If we leave the impression that these unwilling folks are still okay, have we not overruled God? Does our "friendship" mean that we choose to embrace them in spite of God's will? No wonder God feels we are adulterous. He just got shut out.
We cannot adopt the worship practices of worldly religious groups and claim that we are listening to God. We cannot turn God's church into a theater and believe that God is well-pleased. Do we think so little of God that we can ignore what He desires for our own desires?
Paul said he wished everyone were (a Christian right with God) like himself (Acts 26:29). So do I. But all Paul's wishing, and all my wishing, will not change a person who is unwilling to let go of the world. But we will not give up trying.