His mother, Princess Maria Teresa d'Este, was the daughter of the Duke of Modena, also a descendant of Madame de Montespan, and related to the House of Orléans.

His father had specifically chosen Maria Teresa as his son's wife due to her renowned piety and beauty.

After three months of happiness, Louis Alexandre, a jaded hedonist, soon tired of his young wife and resumed his life of débaucherie.

[citation needed] At one point, Louis Alexandre even sold his wife's diamonds to raise money to pay his debts.

After a dissipated short life, Louis Alexandre died on 6 May 1768, sixteen months after his marriage, of a venereal disease at the Château de Louveciennes in the arms of his ever dutiful wife.

We cannot too highly commend the sentiments of piety and resignation and the courage which this prince showed during his long illness, up to the last moments of his life.

On 25 November that year, in a long religious procession, Penthièvre transferred the nine caskets containing the remains of his parents, the comte and the comtesse de Toulouse, his wife, Maria Teresa d'Este, and six of their seven children, from the small medieval village church of Rambouillet, to the chapel of the Collégiale Saint-Étienne in Dreux.