He’s gay; so what?
I’ll admit I don’t like him, although his sexual preferences have no bearing on this.
What you’ve said is EXACTLY the point. ‘Brand Phil’ is based on perfection, he’s the perfect, lovely bland daytime TV persona, with just enough spice to make him interesting (all that stuff about him partying all night with Holly after awards etc).
He’s already had a few knocks this year, co-presenters complaining about him being a dick, being a bit to nicey nicey with Johnson etc.
If he comes out now, it’s “he’s gay, so what?” the media and social media will rally around him, they’ll say he’s brave and wonderful and his image grows.
Alternatively, a headline that says “Phil cheats on wife of 27 years with Man” could ruin him, even if the less Mail-like papers stick with “Phil cheats on wife of 27 years” he’ll be in real trouble. Lots of ‘names’ have never fully come back from a story that knocks their nice-guy image – Jason Manford, Vernon Kay, Justin Lee Collins etc.