Caroline, little sister of Napoleon influenced her brother into having an affair. Openly flaunting it, Napoleon had a son with his mistress, & thoroughly angered his wife at the time Josephine. They divorced soon after.
Caroline then convinced Napoleon to marry Marie Louise, whom she liked.
Caroline helped Marie Louise come safely from Austria to France, & convinced her to leave every trace of her life behind including her dog, so that she might fully assimilate in her new country, & not offend the French people, so that the marriage would “stick”.
It worked out well. Marie Louise & Napoleon had a good relationship with many children produced, & Caroline & Marie became fast friends.
(portrait: Caroline Bonaparte in French formal wear about 1809. Note how the “little white dress” of Regency prevails underneath its ornamentation!)