To answer your question, I think St. Augustine is an excellent intercessor for those struggling with unchastity. Another good one is St. Ignatius of Loyola (the founder of the Jesuits, who was more than a bit of a womanizer when he was younger, I've read).
I've been told by priests that our Lady is an excellent intercessor in this matter as well.
My preference in this matter is St. Augustine, however (who is also an excellent intercessor for theologians or those studying theology, those suffering from sore eyes or eye diseases, and for sinners wanting to repent). :D I like my patron saint.
I have honestly never heard of the particular blessed you mentioned...