No doubt, like many gay people, he was fearful, in advance, of possible reaction.
As it turned out, the reactions varied between that of his father, who regarded gayness as something to be fixed, and that of Sean Og O hAilpin, who was "unbelievable -- content that I'd told him and happy to open up to me about his own life."
Knowing him, I'm not surprised about Sean Og's reaction. This is an integrated, confident, warm man who knows who he is and is happy for you to be whoever you want to be. Just be wary of his handshake. It's so enthusiastic, your hand needs to go into intensive care for a week after he's shaken it.
What's surprising is any expectation of a nasty wider reaction to Cusack's 'coming out'.
Of course, players on other teams in the middle of a row will yell anti-gay abuse.
Same as they'd yell abuse about someone being fat or short or red haired or coming from a different religion.
It's a rage-reflex that doesn't always reflect deep-seated abhorrence. Other than that kind of stupidity, Cusack could have expected a reaction that mirrors just how far we've come, as a nation, since the days when a priest would refuse Communion to a woman known to be "living in sin."
The measure of how far we've come is the Gately funeral, where, from the altar, his husband was acknowledged and welcomed.
One of Brian Friel's plays touches on the moralistic Ireland we used to live in. A character talks about a priest walking around a night-dark field known to be frequented by lovers, poking them with his walking stick and roaring "Are you comfortable in your sinning?" (One of the naked men, startled, tells him the truth: "Please, Father, no. The grass is damp.")
It would be great to believe that, these days, we're all more tolerant, more compassionate, more accepting than back then.
That's not the case.
Many gay people still experience subtle and not so subtle discrimination. But we're a hell of a lot less shockable, as a nation. And it's possible to pinpoint, almost to the day, when that became obvious.
The morning the Bishop Casey story blew, I picked up the newspapers several hours before dawn on my way to the office. At the toll bridge, one of the lads opened the window of the booth.
"The local radio stations say there's a scandal involving Bishop Casey," he said. "D'you know what he's done?"
"According to the papers, he has a teenage son."
"Oh," he said, shrugging. "Is that all?"
A decade earlier, when men leaving the priesthood were being beaten up, the idea that a bishop would not just have had sex, breaching the rules of celibacy, but fathered a son, would have been literally incredible.
That sort of thing didn't happen.
Or -- more significantly -- if they did happen, we never heard about them.
The arrival of television changed everything, not least because of a fearless man named Gay Byrne, himself the most traditional of Catholics, who used his programme to explore ideas and realities hidden in the black-and-white darkness up to that point.
On one famous programme about gay people, a bigot in the audience talked of "homosexual men obsessed with each other's back passages".
Without breaking stride, Byrne told him a hell of a lot of heterosexual men were obsessed with women's front passages.
Once the nation got its breath back, it realised that everything had changed. Forever.
Or maybe we've just shifted the focus of our rage. Away from women "living in sin" and gay men -- to expenses, bonuses, bankers and developers.