He and the child greeted Sulu when the USS Enterprise helmsman visited the base in 2263. Later, during Krall's attack, he ran from the destruction carrying their daughter in his arms. (Star Trek Beyond)
Background information Edit
Sulu actor John Cho insisted that Sulu's husband be of Asian descent, stating, "The reason was that I grew up with some gay Asian male friends. You don't really see Asian men together very often. It's very rare in life. I've always felt that there was some extra cultural shame to having two Asian men together, because it was so difficult to come out of the closet, so difficult to be gay and Asian, that they couldn't really bring themselves... It's easier to run away from people that look like your family. I wanted the future to be where it was completely normal and therefore, aside from the gender, they look like a traditional heterosexual couple. So that relationship, to me, the optics of it are that it looks very traditional on the one hand and very radical on the other." 
Doug Jung described playing Ben as "the really uncomfortable experience of being on a screen with incredibly good-looking, fit people, and not being one of them." Laughing, he added, "I don't recommend it." (Star Trek Magazine Movie Special 2016, p. 91) In a more serious mood, Jung elaborated about the role (which was his first acting appearance), "It sort of came up as a last minute thing. There was an actor they had cast in Dubai – and it is really hard to cast in Dubai, because there are not a lot of local actors – and he fell out for whatever reason and Justin and Lindsey kind of said, 'Listen, if you'd be up for it, it would be great. Cho's up for it.' I was self-conscious about just being up on the screen [....] But Cho's amazing just in the way we talked about it, and how Justin wanted to [portray] it, and how everyone wanted to portray it. It was great to do and I was really proud to be able to do it, because it's not often you get to put your money where your mouth is and it's something we all believed in so strongly."