Here's the thing, if he comes right out and says "yes we are/were dating, no it isn't/wasn't serious" when he's casually with a woman, then when the day comes that he IS seriously with someone and he says "no comment" everyone's going to know something is up.

If he and EO are involved in some kind of commitment, the secrecy could just be that they know the relationship isn't "marriage material" for either of them and they don't want to put it on the record... though off-the-record tabloid leaks are apparently still fair game.

I guess it's also possible that it is over between them and his comments here only mean he's not going to talk about it, whatever it was.