Yes, nearly a year! I am glad to say I can't remember the exact date I confronted him, but he moved out in early Feb so I am going to take that as the year when it arrives.
How to update in a nutshell? Hmm. Ended up leaving my job and going back to university, which was one of the best things I could have done as it has given me a new lease of life and (in 6 months' time, if I keep my head down and don't get distracted by men 
) a professional qualification :).
Things with my ex are OK. We are just trying to make sure DD is happy (we have 50/50 custody) and that we put her first in whatever we do, which seems to working alright so far, although she is going through a real 'daddy phase' at the moment and gets a bit upset sometimes when it's my turn to have her. But I know it's not personal and that she would prob be doing this even if we still lived together. I remember when I was little that I missed whichever parent I wasn't with and it made me sad, so there's not a lot we can do about that except reassure her. He is still with the OW, who split from her own husband. I don't know much about them really, except that he did ask me if he could introduce DD to OW about 4 months ago, to which I agreed. They seem to be getting along OK but I haven't met her yet - I will do so before they move in together, which they are planning to do.
If you could have told me a year ago that I would be feeling OK about all of this - not exactly jumping for joy, don't get me wrong! - but OK, and accepting, then I would not have believed you. Actually, I expect some of you did tell me that! And now I know you're right - it does get better :)
Thanks for asking, WWIFN, and for all the support back then; you (and lots of others) were an absolute bloody lifeline!! xx