Your thoughts about a psychiatrist are good, medicnh; I was just reading a novel where a major character has OCD :-) and another friend got a referral to a psychiatrist for it, saying there were good medical help now for OCD. I found this:

http://www.brainphysics.com/medications.php

But I think a psychiatrist may be able to help her, at least initially, with her OCD but don't know if that will help the marriage; I would also do a bit of marriage counseling as Typo suggests. Your thoughts, feelings, and behaviors in the marriage are just as important as any of hers.