I am grieving it, absolutely, and I always will. I never wanted to have an ex-wife or an unsuccessful marriage.
That said, in my particular situation, I firmly believe it is the healthiest decision for both of us. She was the one who initially voiced the desire to part, and it took me a few days of soul-searching to realize she was right, but that doesn't make it any less sad or make me feel any less like I failed. Our marriage was good for a long time, and I am in mourning for that.