I agree with a lot of the previous posts. Of course there is a chance that your friend may well be confused - however, it might be the right thing for him. But it will take time for him to work this out, and all you can do as a friend is be there and support him whatever his choice.

Don't feel bad about being shocked - it doesn't mean you have a problem with it as such it's just someone you've known for a long time has suddenly told you that how you invisioned them before is slightly different to how they actually feel. You are bound to feel a bit unsteady and it will take you some time to come to terms with it to - even if that is just adjusting to seeing your friend in a different way. The fact that you are worried you are being a hypocrite shows how much you care about your friend and I really think that if you try to accept your feeling at the moment as a transition of sorts, you will begin to get used to this new development. It's also a testament to your friendship that your friend felt he was able to tell you this - i've known many people who felt they could not tell their friends. Don't be too hard on yourself x