If that were the case, no one would bother with marriage. It would be completely meaningless. This is an incredibly naive view.
The relevant question is not whether it's legal nor what one's religion has to say on the matter. The question is whether he showed character, and we can evaluate that by whether he lived up to his word and--especially--by how his wife took it.
Sorry but BS. Marriage is an economical (oiko- in oikonomia---the Greek word that is the etymological origin of economy---means family/home), legal and religious phenomenon. In modern societies the accent is on the first two, and we separate the legal meaning of it from its religious one; the former being an official bond regarding two person and their children, which governs how responsibilities, goods and resources belonging to a family core are parted and used among those individuals. That's the big part of why people bother with marriage (or things like civil unions) even if they are not religious.
Regardless, "living up to one's words" means nothing regarding the validity of a statement. I can say 1 + 1 = 1, but then in my private life behave as if it was 2; that does not affect the truth of the former statement.
The relevant question is not whether it's legal nor what one's religion has to say on the matter. The question is whether he showed character, and we can evaluate that by whether he lived up to his word and--especially--by how his wife took it.