Very, very cruel, and although I'll admit to laughing at some points in the dialogue (more in shock than in genuine amusement), I'm not sure the shame of a region-wide dumping on radio outweighs the girl's infidelity. It feels to me like firing a Tomahawk cruise missile at a mosquito, and pointedly shows the lack of nerve in the guy to actually dump her himself.
It reminds me of the story I once heard of a similar couple with the woman being more than a bit close with a man she wasn't supposed to be close with. Her fiancé had had a PI trail her and make beautiful pictures of the woman in various poses which would put any porn actress to shame. He waited until the wedding was truly well underway, and then, during the festivities after the vows were exchanged, made a little speech in which he urged every guest to look under their chair. They found envelopes taped to them, and upon opening, discovered various 'compromising' pictures of the woman who was now married to a man who did in no way resemble the man in the photographs. He then announced he was going to file for divorce.
That story too has me thinking 'a bit too much, perhaps'.
