For my own future use if nothing else, here are my comments on the matter:
I'm not saying DC might not promote more romance in a given hero's life if he was accused of being gay or homoerotic. There's a fair chance that's why Batwoman started showing up in the post-Code Batman stories. But since Wertham didn't impute homoeroticism to Superman-- just plain old fascism-- I tend to think DC was just indulging in giving their hero a more active romantic life, as long as they could be sure that the female involved would die, lose her memory, etc.
I wouldn't put it beyond the realm of possibility that the Wertham publicity might have made DC hyper-aware of their image for a while, though I'm not sure that they would have remained vigilant about everything for so long. OTOH, DC Comics effectively wrote Catwoman out of existence for about the first 12 years of the Code, so certainly some things twisted their knickers.
A caveat, though, is that sometimes superhero comic publishers also used girl characters both to titillate some of the boys-- the ones who didn't find girls entirely icky-- and to appeal to a potential female readership. So while I don't dismiss entirely the "hey, hey, don't say we're gay" stratagem, it's just one thread in the overall design, methinks.