IB I felt like you did several months ago and still do in little pockets from time to time, but more than anything else I feel back to "normal" as far as the ability to be happy/joyful.
The difference for me is that I defined happiness and joy before only through my marriage. Now I define it in every other area of my life BUT a relationship with a significant other, because I don't have a significant other, nor do I see that changing any time soon.
I am almost at the point where my trust in relationships is so thoroughly broken (romantic ones) that I just don't put any faith in being in something long-term again. It's not just my own situation or the betrayal from my ex, but from what I witness with other people's relationships or even from my foray into dating, where in every case but one, I've been duped or lied to or deceived over and over again, despite being very wary. I mean just this morning I felt a bit unsettled about someone contacting me on match.com and i did a google image search on his photos only to find this is a professional scam-artist who has multiple fake profiles on tons of sites.
So because of all that, I guess I've just started to try to find joy in everything else. And really, everything else in life does amount to a lot. It can amount to something greater, really, than a relationship with a mate. I think you just need to try to keep finding ways to enjoy the things you do that can be seen as not part of the married version of IB.
Not sure how to explain it, but the more I focus on everything that is not part of coupledom, the happier and more content I am.
M45 Bomb 6/09; EA 6/10; Divorced 1/11 Proud single mom of 7 little feline girls and one little feline boy "Fall down 53 times. Get up 54." -- Zen saying