Who is Note Mokoti from The No. 1 Ladies' Detective Agency and what is their importance?

Note Mokoti, Mma Ramotswe's husband, is described as a sexy and exciting jazz musician who charms and dazzles her, then marries her, impregnates her, beats her, and leaves her. In the same way as Obed Ramotswe is Mma Ramotswe's model for a good man, Mokoti is her model for a bad man, with almost every man she encounters considered and/or judged by where they fall on the continuum of manliness between the two.