Comic trivia: Not with Arianna, but in the comics Lex had a daughter (Lena Luthor) with one of his wives, the Contessa Erica Alexandra Del Portenza (1998, Superman v2 #131).
And a follow-on piece of trivia: Before Lena Luthor was the name of Lex's daughter, it had been the name of his sister. In the Silver Age, he did have a (very) few redeeming qualities, one of which was that he did care for his sister... Enough to let her believe he didn't exist rather than to know that she had a criminal for a brother. Their parents had been so ashamed of Lex that they changed their names to "Thorul" so they wouldn't be identified with him, and they told a very young Lena that her older brother, Lex, had died.
Lex did a number of things in the Silver Age to promote her well being. (I can't think of specifics off the top of my head, however.)
Joy,
Lynn
