Is there a chance my son is bisexual or homosexual?

I just added my son to my facebook friend list. I know my son is a very private person, but what I saw come as a shock to me.
He also has a lot of bizarre pictures/artworks that he collects up which doesn’t surprise me. I know that he tend to hang out with alternative crowds and artists especially since he owns and run an art gallery. Most of the picture he have up are of punkish girls modeling. But what strikes me as odd is, he have some pictures of lesbian couples and a few odd guy like Liberace and Andy Warhol and few other guys dressing or looking oddly. He also commented on how good some of the guys in the pictures or his male friend on facebook look, he even use word “hot” when commenting on the guy’s scars.
Despite of him being 32 years old, the closest thing to a long term relationship he ever had since he dumped a long time girlfriend more than ten years ago would be owns a house with a female friend. They have lived together for nearly three years but aren’t in a relationship.
Also he seems to be with a new girl like every month or two but never say he was in a “relationship” or anything. On his facebook, he stated relationship as “it’s complicated”
My son also have commented on how bisexual people are awesome and agreed with someone that everyone is at least somewhat bisexual.
This got me wondering if my son is actually bisexual or even homosexual. So I’m worried that we probably made him feel shameful about the whole homosexual thing because I and my husband used to be really uptight when he was growing up. But we have mellowed down a lot ever since he moved out and realize a lot of our errors. So I’d like to be open with him and let him know that it is ok for him to be who he is and he doesn’t have to hide everything from us. But I don’t want to bring this subject up if it is unlikely he’s bisexual or homosexual as it’d make thing really awkward for both of us.