noun

a man who behaves dishonourably, especially towards a woman.

her adulterous cad of a husband

scoundrel,rogue,rascal,good-for-nothing,reprobate,unprincipled person,cheat,swindler,fraudster,trickster,charlatan,villain,bastard,beast,son of a bitch,SOB,rat,louse,swine,dog,cur,hound,skunk,heel,snake,snake in the grass,wretch,scumbag,bad egg,stinker,scrote,blighter,sleeveen,spalpeen,rat fink,rotter,bounder,ne’er-do-well,blackguard,miscreant,knave,dastard,vagabond,varlet,wastrel,rapscallion,whoreson,shit,bugger,motherfucker,mother,mofo