Is Divorce a Sin?

I have been battling with this question for a while now and I can’t flush it out. I have a couple of parishioners who are going through separations. They are wonderful and caring people who got into marriage with their whole heart and soul. Yet, their spouse had something else in mind. Person 1 her husband walked out on the family with no real good excuse. Person 2, his wife had an affair. It is thought that the husband of Person 1 probably had an affair but there is currently no proof or admission.

I understand Jesus’ stance in Matthew 5:32, But I tell you that anyone who divorces his wife, except for marital unfaithfulness, causes her to become an adulteress, and anyone who marries the divorced woman commits adultery. It seems that Person 2 is in the clear from the guilt of the divorce, since his spouse had an affair. Person 1 though is riddled with guilt that she is committing a sin, a GREAT sin against God.

My problem with this thinking goes beyond my compassion for her in this situation. I do not like the idea that people are throwing guilt upon the guilt they both already have. I do not think that is what Jesus has in mind for ministering to people who are going though this. You cannot DROP a rock on the internet without finding some type of DIVORCE WILL SEND YOU TO HELL page.

What should a pastor do in helping a parishioner understand, make sense, and find God in a divorce that person doesn’t want or is forced into? I think one of the major issues these people go through is dealing with this questions, Is divorce a sin? How do we as pastor's answer that?