Basketball Coach Resigns After DWI Arrest - Why?

According to reports, Hofstra's men's basketball coach Tim Welsh resigned only 3 days after he was arrested and charged with DWI.  The question that I ask, "Why, why would you resign after only an allegation of Drunk Driving?"

"The university accepted the resignation in the best interests of the university and of the men's basketball program," Hofstra spokesman Stephen Gorchov said in a statement.  According to the report, Welsh was to be paid $3 million over the next 5 years.

Was this really a resignation from someone charged with DWI or did the University force him to resign.  My guess - the University forced him to resign pursuant to some morality clause in his contract, though that was not in any report I have seen.  This begs the question, "Is an arrest for DWI really a morality issue."  There have been coaches that have certainly survived a DWI arrest and conviction.  Let me know your thoughts on this issue.