It's kind of a minor thing, but did you ever notice that a lot of Stan Lee's male characters tended to fall for bad women? Let's see, we can start off with Hawkeye:
1. Note that it is never the leading male character who falls for the bad girl. Stan senses that this is bad characterization for his heroes, even though it never really hurt Batman in the case of Catwoman, for example.
2. It tends to be the main supporting actor. Hawkeye doesn't fit that pattern, but Foggy and Balder certainly qualify and by that point Happy Hogan had largely disappeared from Iron Man, so Jasper Sitwell was the number two.
3. Most of the evil women "reformed", although you can make an argument that some of them never really were quite as bad as they appeared. It turned out that the Black Widow's parents were being held hostage in the Soviet Union and eventually she rebelled against her communist masters and became a heroine. Debbie Harris did reform and began dating Foggy again, eventually becoming his wife. I am unsure about Karnilla; at one point she did help Asgard due to her fondness for Balder, and Balder eventually admitted his love for her. Whitney Frost's tale is more complex; in that original Iron Man saga we learned that she was genuinely conflicted in her role as the head of the Maggia, having taken it over from her father, Count Nefaria.
4. Stan used these relationships to open up new plotlines or to add new dimension to his characters. Hawkeye was allowed to become a temporary villain while leaving open the possibility that he would reform and become a hero, as in fact he did with the Avengers. Debbie was paired off with Foggy to clear the decks (twice) for Matt and Karen Page to become an item, although in neither case did it last for the latter couple. Balder and Sitwell had both been pretty much portrayed as Boy Scouts (quite literally in Jasper's case); this was a way of humanizing them.
5. Aside from Batman, I can't think of a comparable situation in the Silver Age DC, and even his relationship with Catwoman was more of a Golden Age and late Bronze Age affair.
6. Marvel only reversed the roles once; you can make an argument for Sue Storm and the Sub-Mariner setting the template for what came later. DC did have Wonder Woman and Supergirl fall for a few rats at the end of the Silver Age, although in both cases that was more due to short-term plot demands than long-term characterization.
Update: Johnny Bacardi points out that Archie Goodwin actually did the scripting for the Iron Man series by the time of the Sitwell/Frost affair.
Update II: Debbie Harris was apparently introduced during the one issue that Wally Wood scripted of Daredevil, per Fraser Sherman.