What about Marianne of the Netherlands and her (ex) hubby Albert of Prussia?
Yes, that was quite a scandal too. Even more so, because she ran off with her second husband and their son would tragically die very young.
Very tragic is also Marie of Mecklenburg-Strelitz and Count Georg Jametel. He was having several affairs including one with Infanta Eulalia.
Marie applied for divorce and said that he only married her for her money (which was most likely true). It came out however that she had a child out of wedlock, born before her marriage. To restore the honor of his sister her younger brother, Karl Borwin, challenged her Ex to a duel, dying in the prozess.
Marie later married a Prince of Lippe.