I'm assuming this means;
"What The Fuck In the World Would Mother Teresa Do?" I saw the letters in a recent article in the New York Village Voice by Dan Savage.
"You might be able to extract a promise from him under duress, WTFIWWMTD, and get him to agree to sexual exclusivity as a condition of going ahead with the marriage. But that will just result in you facing the emotional and physical risks of an open relationship without the honesty and accountability that can mitigate those risks." Village Voice, April 2, D. Savage