So why does being gay matter so much?

This is a good point.

Also if you weren't out before and you're still not now, how has being gay ever been an interesting thing about you, from the perspective of others of course? Maybe it's more the case that now that you don't feel it is such a big issue to be gay, you are looking beyond it, at other aspects of your life and personality and that is where the real questioning is.
It's easy for your sexuality to overshadow the rest of your life and if you are used to hiding that part of who you are from others, perhaps you have become accustomed to holding back in other areas too. Think about the things that really interest you or that you'd enjoy doing and consider why you haven't allowed yourself to 'become more interesting' - in your opinion. Could it be that you worry about others judging you for liking those things?