Tayla reportedly ended things with Grant after finding out he had a 'secret girlfriend' before entering the villa.
"Me and Tayla spoke the night before (her break-up post) and I honestly thought it was more of a lover's tiff or an argument, as most couples have'," Grant told the Daily Mail, also revealing he found out about their split on Instagram.
"I didn't expect it to go up on Instagram... I didn't know she (Tayla) was going to do it all. Firstly, I didn't think it was over and when I saw that... what are you going to do?," he added.
Grant took to Instagram last week to explain his side of the story, revealing he split with his ex-girlfriend Lucy Cartwright before entering the show.
"Going into Love Island that girl (Lucy) totally knew I was going in there so I did break up with her before Love Island, so it was finished. I lied about that to Tayla and I totally regret that, it's something I'm not proud of. Tayla doesn't deserve that at all and I 100 per cent regret it," he said.
Tayla, 21, took to Instagram last Thursday to confirm the split in an emotional post, which comes just two weeks after declaring their love for each other on Love Island's finale and splitting the $50,000 prize money.
"I want to take the time to thank everyone who supported Grant and I during our Love Island journey and especially everyone who has continued to support us since," she started, before explaining that she has to continue be true to herself and her emotions.
"But it’s with great heartbreak that I write this post to inform everyone that Grant and I are no longer together, but will remain amicable despite the circumstances.
"I hope everyone can understand that the last few days have been very emotional and overwhelming for me and that you can all respect my decision."
This article originally appeared on WHO