What justification would make divorce worse than adultery? While I'm not talking salvation here (I understand grace) there is a sense in which some sins are more offensive to God then others.  Scripture is replete with examples of God's hatred for adultery (read pretty much any prophet!) and divorce (Malachi, Matthew, etc...).

Recently, I had a discussion with another pastor who was counseling a person who had created what I believe to be a false dichotomy - the counselee believed himself to be incapable fidelity to his wife, and so felt there were only two options - divorce or adultery.  (The counselee's justification was 1 Cor 7:9 "But if they cannot control themselves, they should marry, for it is better to marry than to burn with passion"). The thing that was interesting to me was that it was suggested that adultery was better than divorce.  The counselor suggested that if the counselee was incapable of being true to his wife, that it was better to have an affair than to terminate the marriage. 

Now, leaving aside any personal specifics (this is not a pastoral advice question!), I'm wondering what is the logic of holding the sanctity of marriage over fidelity within it?  In other words, what is the biblical or extra-biblical justification for suggesting that adultery would be preferable to divorce.

I'm looking for either an exegesis of Scripture or Pontifical statement that would be the basis for making such a counsel. Appeals to the sources of tradition for any denomination are accepted - I'm just trying to understand what the justification is for stating that divorce is worse than adultery.  

Barring that, the inverse - if someone would make the case that adultery is worse than divorce, I'd be interested in that exegesis as well.
Marriage is more than sex. When you enter a marriage you take on all sorts of other obligations - to love and support your spouse, to care for them in sickness, to provide for your mutual needs, and to act as parent to any children you might have. If you deliberately choose to leave a marriage you are abandoning all those obligations as well as the one to remain sexually faithful. Committing adultery is, well, just sex. 

However you should probably avoid trying to read a theological point into a comment made during counselling. The counsellor may be exploring ideas rather than making a theological statement.