NC has been really hard for me in terms of my xN until last year. i felt really "in love" with him, and so hurt and betrayed and misunderstood...i just HAD to make him understand somehow, or at least defend myself against his crazy accusations. then he ended up with all of my stuff (funny how that happens), extorted money from me to send me my stuff or he'd "get rid of it", never sent the stuff, told me he'd gotten rid of the stuff, and 8 years later, still tries to find me to ask me if i still want my stuff....it's crazy-making.
after all of this, i still, for some ungodly reason, felt like maybe if i just was friendly in a superficial way toward him, he'd stop being mean to me and behave like a normal human being. it wasn't until last year, when he began talking badly about my married friends to me (saying they were having affairs, etc) and him not respecting my boundaries when i told him to stop telling me about my friends, i didn't want to know, (he'd keep telling me more and more), that i had to block him on myspace and email for good.
just time to let go. it's really sad, this NC thing, because i'm quite good friends with my other ex-boyfriends. he's the only one i can't have any contact with whatsoever. it makes me sad, because this is someone i shared an important time in my life with, someone i loved deeply, who basically has to be dead to me, for all intents and purposes.
but, there is the peace of mind that comes with NC...you just have to keep reminding yourself why there is NC to begin with, i think.