They always look great together. I'm still not convinced Matty isn't bi/gay. The majority of non-diving-team tweets he's liked on his Twitter (which he's not used in a year, admittedly) are from gay guys, and an old twitter account which is in his name and lines up age-wise and date-wise with when he switched to his more recent professional account, even suggests explicitly as such. Even in interviews he's said before that 'so what' if he were, and most recently in his Q&A when asked about relationships, his response wasn't at all gendered before he switched to joking about how his housemate cooks for him anyway.
I don't think for a second him and Tom are at it, but I do wonder a lot whether the shared experience is part of why they get on so well. No matter what he is though, he's hot, and that's the main thing!