While I'm not completely happy with any of the voting options we have to choose from, I think "sexually fluid/open-minded" comes closest to describing Eric's sexuality. Like Graeme I find the "sexually fluid" option a bit offensive because to me it implies Eric would be open to a casual fling with a guy. I just don't see that happening. However, due to Eric's life experiences of living with non-hetero people I could see him being "open-minded" enough to getting involved with the right guy.
I need to go slightly off-topic here to hopefully spark a serious debate.
This whole issue actually bothers me. Why do we need to speculate about anyone's sexuality? Why do we feel the need to make anyone into something they might not be? In a way it lends credence to the homophobic accusations of gays trying to convert straights to being gay. We all know that's BS! You are what you are and that's it be it gay, straight, purely bi, bi with certain leanings, or just curious.
Personally I'll be happy for Eric regardless of the sexual choices he makes. He's still young and having fun living the life of a rock star. That's great. We should all be so lucky. But eventually I hope he'll find the right person to make his life happy, contented, and complete.
ADDED: I wrote this and previewed it before seeing Kevin's reply. I'm too tired right now to go back and address the issues he raised. But I think it's a good start to the debate I was hoping to start.