The first half was excellently written, funny, and overall entertaining. The second half seemed as if the author didn't know what to do with the characters anymore and it became somewhat tedious. Colin came off as petty and Penelope, a great heroine up to that point, became... boring. She seemed to be TOO grateful that a 'Super Bridgerton' had the magnanimity to actually marry someone as 'low' as her. It was implied throughout the novel, even by the hero himself, that it was a great thing on his behalf to have married her, so the whole 'magic' of the story was destroyed. 
 The 3 stars is for the beginning; the rest deserves 1.