What about the letters between Pozzi and his daughter Catherine makes his wife Thérèse call them 'love letters'?

Pozzi was often distant, living in a separate section of the house than his daughter and wife and isolating himself in his home office at times. Catherine's devotion to her father was intense, especially given the complication of his marriage to Thérèse, leading Catherine to want to reconcile her parents, chastise her father for his errant ways, and receive from him all the love and attention she wants and which she senses he gives to the public but not to his family. When exchanging letters, father and daughter poured so much of their emotions, both happy and sad, into their writing that Thérèse upon reading them could not help but sense that level of emotional intensity resembled that between lovers.

How did Jean Lorrain likely feel about being known as the poor man's Montesquiou?