Here’s what I think about the Saiyuki characters’ sexual orientations and whether their virgins or not. xD
Gojyo: Of course he is definitely not a virgin. He obviously slept with many women prior to the journey, but hasn’t had much opportunities to do so during the journey. Actually… I’m not sure…
Actually, Gonou’s and Kanan’s relationship is quite explicit in the manga - it’s one of the first things he tells Gojyo when he’s recovering and they start to talk. One thing you may have missed: when Gojyo is asking about the person whom Gonou is mourning, Gojyo holds up his pinky: that’s a gesture that specifically refers to someone’s (female) lover. And then Gonou says “She was also my elder sister” and asks “Do you think the less of me?” (And Gojyo, nonjudgmental sweetie that he is, says “Naaah, some people .. go for that, I guess.”)
And then there’s all the flashback/sex dreams it’s implied he has in the Chin Isou arc.