Roy marked his 100th one-day international outing with a solid score of 73 from 60 deliveries as England powered past the Netherlands to take a 2-0 series lead.
The victory has come three months on since Roy was handed a two-match ban by the Cricket Discipline Commission for an undisclosed offence.
The player admitted he endured a turbulent start to the year as he spent time away from his son in order to compete for the Pakistan Super League.
He said: "Things mentally weren't right with me at the PSL. I was in a weird place because I was playing good cricket but I wasn't enjoying myself, I wasn't happy and it was just a dark time.
"It was just a good two months to come home and live a normal life for a bit after a tough couple of years.
"(There were) a lot of months away. Over 50 days of hotel quarantine the year before and then having a child in January and having to spend time away from him was just a bit too much."
Roy's first career 50-over innings for England came back in 2015 when he dismissed for a first-ball duck. Just four years later though, he was part of the squad which won the world cup.
Looking back on reaching 100 ODI appearances, he said: "It's an incredible feeling. It kind of crept up. The hundred feels very special.
"At least the 100th game was better than my first innings! But it's an incredible feeling - whether I got 70 or nought here, it would have been a special day."
Roy made just a single in England's world-record 498/4 in the opening match against the Netherlands, bowled by his cousin Shane Snater. The opening batter laughed off the dismissal on Sunday.
"He did buy me a drink," Roy with a smile. "Water under the bridge - we don't talk about it any more."
England take on the Dutch in a third and final game on Tuesday.