Things change? I'll say. Maybe we should stop calling them wedding vows and refer to them as "non-binding but well-intentioned wedding hopes."
Michael's betrayal of his wedding vows are of a wholly different magnitude and not analogous to your point about the commonality of divorce and remarriage.. While still married to the woman he vowed to love and honor till death, he took up with another woman and started a new family.
Nothing new or shocking there.
That too, is done a lot.