Well I'm just touching middle aged and like him irrespective of his sexuality. AFAIK, most of the 'middle aged ladies' I know love a gay man. John Barrowman has played male romantic leads in the West End, is well loved and I don't think it would matter a jot (and it wouldn't be that much of a surprise!) if MB came out as gay. I just don't think he owes it to anyone to reveal it if he doesn't want to. What he 'owes' the public is to turn in high quality performances when he is paid well to do so (unless he's ill, of course).
Even if Cathy Mc Gowan is a 'beard' they obviously have a good relationship that works well for them. Karen 59 seems to know him quite well and I believe what she says. Contradicts the story I heard somewhat (about him being a diva) which was only third hand and I am glad to be corrected.