Master Chief just had sex for the first time in Halo's canon as part of episode eight of the Paramount show. As a character, Master Chief has always been focused on war, fighting, saving marines, and just generally defending the universe, without any kind of hint towards him having a sexual side.
The only thing close to that we see is his relationship with Cortana, an AI that doesn't have physical form for most of the Halo games.
Related: None Of The Bad Things Have Been Fixed In Halo Season 2 That description only really applies to the Master Chief we see in the games and books, however.
The Paramount iteration of the character, played by Pablo Schreiber, just proved himself to be a very different chief indeed in episode eight of the show, where he is shown having sex with a new character to the show, Makee.Read more on thegamer.com