Roberts, as captain of the North Queensland Cowboys, is back in Britain, where he was born 32 years ago. He "came out" with the publication of his biography, Finding Out, in Australia late last year.
His book will be published here this autumn. The story he has to tell paints an extraordinary picture of a man balancing two apparently contradictory sides of his life.
Roberts has played 13 years of rugby league at the highest level, for South Sydney, Wigan, Manly, New South Wales and Australia, before his present club.
Although regarded as one of the game's fairest players, he is also one of its hardest, having overcome a horrendous series of injuries - and a tendency to bleed like a battered heavyweight - to remain one of its most-feared tacklers. Julian Clary he is not.
"I've never been happier with my football than I am at the Cowboys. That's because there's no more speculation about my private life, because it's all out in the open," he says. "I got sick of all the rumour and conjecture all the time. Every time I walked into a room, you could see people thinking, `Is he this? Is he that?'
"There was plenty of verbal abuse, on and off the field, but I accept that as inevitable. I'd get that if I was black, if I was overweight, if I was cross-eyed. There's less of it now, because what are they saying that you don't know? If anyone has a go at me about it now, I can say, `Great, very original.'
"I cop more of it in England, because it probably has more of a novelty value here. But it doesn't worry me any more, that's how much at peace I am; it doesn't bother me what anyone thinks of me. That's their problem, not mine. What you see is what you get, that's my attitude now, although it's taken me a lot of hard knocks to get to it."
Roberts accepts now that his involvement in the gay scene in Sydney - a city which, in an astonishing change of attitude over the past 15 years or so, has taken to regarding itself as the gay capital of the world - was "the worst kept secret in town".
"With hindsight, I wish I had come out 10 years ago."
That would have been considerably more difficult. What is possible for a player of proven quality and irrefutable courage would seem a terrible risk to a young player making his name or, say, a slightly flakey winger with a dodgy defence.
"I suppose it's helped to change perceptions of gay people, but if people had those perceptions in the first place it was because of ignorance, and ignorance, in my book, is no excuse. But it is the reason that so many people have so much trouble coming out, although there's a lot more gay guys out there playing."
Although, as he says, it is not part of the popular perception of a rugby league player, Roberts is not unique in his orientation. Old-timers in Sydney recall an international winger of the 1920s whose homosexuality was as well-kept a secret as Roberts', while there was a flurry of interest in the Sunday tabloids a few years ago over a former Great Britain wingman who had apparently taken to wearing women's clothes. However, none of the current generation of players in Australia have followed Roberts' lead in coming clean about their lives.
"I don't think anyone else has been as lucky as me," is the way he explains it. That luck centres around his partner, of whom he says: "I wouldn't change a single thing in my life, because if I did I wouldn't be where I am and with who I'm with, and I wouldn't want to risk losing any of that."
Even more crucial, perhaps, has been the attitude of his parents, a couple of "Ten-pound Poms" who migrated from Battersea to Sydney when Ian was a few months old.
"The book was more or less for my mother and father, to let them know that I was OK. They have been fantastic. My mum and dad would be proud of me if I was happy and a street-sweeper. They are as proud of me as they are of my brother and two sisters."
Without their support, Roberts would never have gone public. As it was, he combined the revelations about his life with a decision to leave Sydney and play for the Cowboys in Townsville.
On the face of it, it was a perverse choice, because the popular image of Townsville is as red-necked and blokeish as Sydney is diverse and metropolitan. "But I love it there," he says. "I'd never go back to Sydney."
His partner, who is at university there, is equally enthusiastic, but part of the contentment clearly lies in not having to pretend any more.
"It was a gradual thing, but in the end it wasn't a problem for me to come out. What I'd finally got sick of was wanting to show affection for my partner and not being able to." Now they do and - even in northern Queensland - that is not a problem either.
Roberts has even been made captain of the club, something he regards as a genuine honour.
"Our coach, Tim Sheens, just asked me if I thought I was up to it. It was very flattering. I can't think of anyone I've played with who I haven't got on with. If they don't get on with me, that's their problem, not mine.
"As a captain, I don't talk much on the field, more a matter of actions and leading by example."
Roberts has done that throughout his career. A first-grader at South Sydney in his teens, he came into a game that was considerably more brutal than it is now and survived and thrived by his own code.
Part of the respect he commands stems from his combination of complete physical commitment and rigid discipline. Even though he must be on the receiving end of more sledging than any other player, as well as the game's standard physical provocations, it is virtually unknown for him to retaliate. "It never crosses my mind to lash out at someone on the field. I'm too busy getting on with the game."
The result is that he has never been sent off in a first-team match. "Actually, that isn't quite true. I was sent off for elbowing when I was with Wigan, but they found out they'd got the wrong man."
His season at Wigan as a 20-year-old was a formative experience for Roberts and he came close to abandoning Australia in favour of the country of his birth, using his British passport to pursue a career here at club and international level. "I was tempted," he says, "but it wouldn't have been the same as playing for Australia. I feel Australian."
Back home, he achieved his ambition to wear the green and gold, although injuries - to the groin and knees, primarily - kept him out of two of the three Kangaroo tours that he would surely have made.
That is why, despite loathing the boring routines of touring, he is keen to be back with Australia for the Tests this autumn.
"I'm playing better than I was two years ago and I feel that I've got several seasons left in the game. I'd even like to play club football in England again. I've always loved the place and I've come back at least once a year on visits.
"I'd like to say it was to see people I met at Wigan, but it's really been more to do with people I've met on the scene."
During this visit, which will conclude with North Queensland's fixture against Leeds on Sunday, Roberts has been talking to Hull, who are keen to add him to their squad for next season.
"At the moment, my commitment is to North Queensland, but at some stage I could see myself playing for Hull.
"I think I would enjoy it there, but a lot depends on my partner. I wouldn't go there without him and I wouldn't want us to do anything he wasn't happy with."Reuse content