I'm not going to lie - the first few months to a year is not easy. I'm 2 years out and still have problems dealing at times. You will need a lot of venting and a lot of support. Surround yourself with (trustworthy and empathetic) friends and family. See if there are any divorce support groups in your area - our local one was a huge help to me. There will be a point where friends and family get sick of hearing it (well, mine did anyway, but they aren't super supportive people) and it was nice to be able to vent to a group of people who TOTALLY understood.
I have an inkling of what you are going through. My ex is a narcissist as well (actually, he has a lot of AsPD traits as well) and I was shocked that after 15 years together he walked away like it was nothing. Kept having his fun, while my world (and the kids' world) was falling apart. I felt used too. I felt like half my life was wasted. It was definitely eye opening that another human being could have that much callous disregard for someone who had shared his life (and sacrificed for him) for that many years. When I begged him to try to work on it, he told me *I* was being unfair to *HIM*. 
<----there's the rolling eyes smilie - you will need that one a lot too. Found out later he'd been having an affair for years, since our youngest was a newborn. Nice. Also found out pretty darn near everything I thought to be true wasn't. Even things he didn't need to lie about - he did. Be prepared for all kinds of shocking revelations.
Post as much as you need to, there are plenty of people who understand. Hugs to you.
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