"are we to deduce he didn't know he was gay until a few years ago, or that if he was it didn't trouble him til a few years ago?"
I would take that to mean that he know he was gay, or maybe bi since he got married, for much longer, but keeping it hidden only started to trouble him in the last few years.
"if those were recent conversations, why did he not open up to his wife at least long before?"
Perhaps because he felt he couldn't admit to it at all, then felt it was too late to do so, but eventually couldn't live with the secret any longer and made the decision to tell her for his own peace of mind.
What sympathies I have are for all concerned; not that I think of it much. It's some celeb's life not mine, nor the life of someone I know. Big news story today apparently (although Lord only knows why), but next week's chip paper. Not going to take the whole world's concerns on my shoulders, they'd be too much of a burden.