Phillip is not abusive to Marina in the books. Marina is mentally ill, and he tries to help her but cannot. He actually rescues her from her suicide attempt, but she succumbs to illness after. He does turn over the care of his children to their nanny and his household help in his grief, but part of that is because he feels inept as a parent due to his own childhood abuse.

As far as Theo goes, a man like Benedict would be much more likely to be able to marry "beneath" him and get away with it. Also, in the books, Sophie is a daughter of a gentleman, albeit illegitimate. Theo is not, and a woman marrying beneath her would be censured much more severely.

Stop screwing around with the books, Bridgerton writers.