I too have found that the less contact I have with my stbxah the better off I am. And when I have contact with him (even if it's just the basics about our 2 D's) it stirs up feelings (I'm less in the "I still love him" place-- at least right now that is-- and more in the "I just wish I didn't have to have any contact at all with you" place) and makes it a lot harder to feel the kind of calm and detachment that NC allows.
I don't have a solution to how to make contact not hurt/suck etc... Maybe just knowing you're not alone in feeling as you do and in finding it hard will make it a little better? I know for me sometimes that's all there is and that helps....