The whole marriage thing was obviously motivated by Lois and Clark
Nope. They were engaged for years before L&C. Superman #50 came out in 1990, while L&C came out in 1993. When L&C was being planned out, the L&C folks didn't -want- them to get married, which led to the "Death of Superman" and Dumbsday. Deborah Joy LeVine, the original L&C producer didn't want them to get married anytime soon. In the first season, she talked about their being married as maybe being a series finale or something, and specifically mentioned that she didn't want it to tank like Moonlighting. Meanwhile, in comic book land, because of the unexpected success of the Death of Superman stuff, they were hungry for the Next Big Thing for Superman -- marriage. In L&C-land, none of the Powers That Be seemed to get "romantic tension", Deborah Joy LeVine was pushed aside, and the comic book folks got their wish for a wedding.