Marcel, Falco & Gabi aside, Bertholdt possibly, as he seemed too shy & enamoured with Annie to attempt anything with anyone else; and Zeke, as I view the guy as aroace, assuming he (and the others) wasn't sexually abused as a child, which I suspect was common at that time and would have affected young Eldian candidates and Warriors, including Porco and Pieck. Reiner, I believe fucked round a little on Paradis until he realised he was gay; and Porco I HC as promiscuous, regardless of the abuse (until he got together with Reiner), as opposed to Pieck, who would have avoided sex (and perhaps tried to make herself as unattractive as possible to men). Colt, I don't really have an opinion on, as it could have gone either way. He could have got drunk one time and done something stupid he'd regret later.