Did you know that Batman was the first superhero to get permaently dumped by his love interest?
Back in the day, every superhero hooked up with their female co-star (eventually - but there was a sense that "yeah, they'll get married and setle down eventually). While Batman and Julie were actually engaged, she broke it off in DETECTIVE COMICS #49.
Of course, The Cat (later the Catwoman) was introduced a few months after Julie, and we've seen where that's gone (and if you ask me, it's about damn time).