The 23-year-old made the decision to leave the villa in South Africa after realising he still had feelings for someone else while "coupled up" with contestant Paige Turley, a Love Island spokesperson confirmed to Sky News.
Ollie's decision to leave comes amid claims he has been involved in trophy hunting in the past, with Ofcom receiving 231 complaints after pictures emerged online that allegedly show him posing with dead animals.
An online petition to remove him from the ITV2 series had been signed by more than 38,000 people at the time the news of his departure was confirmed.
However, explaining his reasons for leaving, Ollie will say in the show's beach hut: "I have to be honest with myself, and everyone, that I do still love someone else… I have to follow my heart in this scenario and it would be wrong for me to ignore these feelings.
"At the end of the day, this is Love Island and it's about finding love. If I carried on anything with Paige, or any other girl that might come into the villa, it wouldn't be fair on them."
A listing with Companies House shows that Ollie is the sole director of Cornish Sporting Agency in Cornwall, which gives its nature of the business as "hunting" and "trapping".
He has claimed to be heir to the Lanhydrock estate in Cornwall, and said his father is Lord of the Manor of Lanhydrock.
However, the National Trust has reportedly said it owns the original estate, but it could be the case that his family home is called Lanhydrock too.
Paige, 22, is the ex-girlfriend of chart-topper Lewis Capaldi, and has already spoken about her famous ex on the show.
Love Island launched its first ever winter series on Sunday due to the huge popularity of the summer version.
Once again, contestants, known as islanders, will couple up with each other in an effort to find love - and win a £50,000 cash prize.
The show is no stranger to controversy, and has previously been criticised for its after-care processes in the past after two former contestants, Mike Thalassitis and Sophie Gradon, took their own lives.
Presenter Laura Whitmore has taken over hosting duties from her friend Caroline Flack, who had been at the helm since the series relaunched in 2015 but stepped down from the winter show in December after being charged with assault.
Flack has pleaded not guilty and is due to stand trial in March.