I'll start off by saying that I'm not yet sure weather or not this interepretation should be taken seriously. Well, that's up to you to judge.
Someone said ages ago on a thread that I cannot remember that Modern Love was a phase used in the gay circles for homosexual love. that got me thinking, is Modern Love actually a "hidden message" to Bowie's sexually confused fans? Looking at the lyrics, the song starts with a most obvious hint towards this:
I know when to go out
And when to stay in
Get things done
Or in other words, I know when it's acceptable to admit that I'm bisexual, and when to hide it to get to be a huge pop star. Soon after that, he also reassures us But things don't really change, his still what he is. But yet, other parts of the lyrics give the impression that he is torn between homo- and heteroxyality, as David sings he's Never gonna fall for Modern love but yet
Modern love - walks beside me
Modern love - walks on by
Perhaps meaning that no matter how much Bowie tries to deny it, he will be always remembered as the bisexual rock star. But still, Bowie tells us there will be no confessions.
Well, that's that. As said, don't take too seriously.