Acrimonious

Tom and Mary had an acrimonious divorce and custody battle for their children.

Divorce can put mutual friends of the divorcing couple in a difficult position, particularly if it's an acrimonious split.

The band's split was acrimonious.

The old man […] began to suffer in the body as well as the mind. He had formed the determination of setting out in person for Dumfriesshire, when, after having been dogged, peevish, and snappish to his clerks and domestics, to an unusual and almost intolerable degree, the acrimonious humours settled in a hissing-hot fit of the gout, which is a well-known tamer of the most froward spirits, […]

[I]t is sufficiently evident from the physiology of man, that boils and eruptions cannot be produced in perfectly healthy persons through the action of water, since water is a matter the most conceivably mild, and since boils produce a feeling always painful, and more or less acrimonious and corrosive, which can only be caused by acrid corrosive matters, or by biting animalculae which form the boil.

Sanguinarina, as procured from the sulphate, is a yellowish gray powder without odor, and almost without taste. A slight acrimonious impression is developed after a time upon the tongue from the partial solubility of the alkaloid in saliva.

Theſe points are diſcuſſed with the ability and learning which diſtinguiſh the Right Reverend Author's [Samuel Horsley's] publications, but not without acrimonious expreſſions of contempt and indignation againſt his opponent [Joseph Priestley].

Lord Aberdeen is indignant that he is described as the tool of Russia, and to prove his independence, vows that he has, when Secretary of State, written very "acrimonious" despatches against that Power. Secretaries of State ought never to write "acrimonious" despatches. […] If the letters of Lord Aberdeen to the "foreign conspirators," who are his correspondents at Paris and elsewhere, had been a little more acrimonious as regards Russia, affairs might have been better, […]

Let us impress upon those members of the Council who were so vehemently acrimonious in their denunciation of the licentiousness of the Vernacular Press, almost to the verge of betraying the least little soupcon of personal feeling, that we are not pleading, in the noble words of one of the greatest of Englishmen, 'for the introduction of licence, but we only oppose licensing.'

That would be a way more acrimonious custody battle than the one my parents had over me.