What does payment have to do with it? A little common sense & a little respect for people is not nullified just because money has paid hands.

This wasn't a choice between keeping his wife alive and speaking at a conference, or annulling a marriage! His wife knew he'd be speaking at a conference. She's an adult and is surely able to read a newspaper at a coffee shop, find an art gallery or whatever else for a couple of hours.

Non-speaker could've insisted on speaking to his wife to arrange a time to meet afterwards, fulfilled his presentation/speech, then written a complaint about lack of flexibility later.