Hey, um, well, he mentions his sexuality in this interview:

Zac: Yeah, I mean I grew up in a small mill town in Washington so I feel like, in spite of my heterosexuality, I was kind of chastised in the same way I may have been if I…and I guess that’s kind of arrogant. 
Rachel: But you really did live through the treatment of… 
Zac: Yeah, I may as well have been a homosexual. I certainly was not well received in my home town. 

From what I can gather from his public persona and the themes of PG’s music, he’s not the kind of person to lie about it. I think it’s best to respect what he’s decided to share.