Thanks so much for all the welcomes, guys. There was part of me that wondered whether NC was really necessary and whether I really needed to be on this thread (yes, the masochistic part that's still also in total denial).
But the amount I am relating to what you're all feeling and saying tells me this is where I need to be. 
I broke no contact my deliberately turning up to somewhere I knew he would be (looking fabulous, obvs
). My reason? I honestly don't really know. The 'missing him' had been coming in waves but was so much better on the whole nearly 4 months in. I think I just talked myself round because I was feeling so much better about myself. Which was obviously stupid, because the reason for me feeling better and more powerful was sticking to the NC!
Life was also hard in other ways (my work was mental, kids had flu etc) and I felt I needed / deserved a boost and some excitement in my life. There is still part of me that's glad I did it, too.
Because I did get that excitement and obsession, but just coupled with diabolical levels of disappointment and the inability to really care about anything else in my life.
I feel like if I had reached out somewhere like this thread at the time, I would have talked myself round and stuck to the NC.
But I have learned lessons for sure. And it only took me a few weeks this time to get back to the point of NC. Last time it took 6 months! So I'll just try to take the positives and move forwards.
Even though I haven't seen him or been in any contact since last Wednesday, I think this will be my Day 1. Because he didn't turn up for something today, which has made the UTTER RIDICULOUSNESS of this whole situation come crashing down on me..
for all of us. You guys are honestly great. Am working my way through the whole thread just now.