This ... MLC thing ... well in a word it just stinks. I have a group of buddies I have connected with whom all have gone through this. We are all at various stages but atleast 2-3 years post BD, there are a couple who are still with the MLCr, a few who like me are still going through a long drawn out process, and a few who were divorced very quickly.
Obviously my involvement with this site I am not one for divorce, in fact it is for this reason I am still going through the process 4+ years post BD. (along with a MLCr who yelled from the rooftops she wanted D but never really acted on it) Anyways, my point is that I actually think the ones who quickly divorce heal and get back into a better life much faster than those of us who have been swimming in the limbo muck. In retrospect I have few regrets but this is one area I which I would have acted a bit more swiftly tbh, but we all are where we should be and we progress at different paces .... as does our MLCrs.
The fact your MLCr is talking remarriage and all about you meeting OM2 just illustrates how gone she is. She has yet to meet the dude .... which really just adds to that fantasy she has built up in her head. I would imagine she will continue to chase 'happiness' in various forms for quite sometime. Replay, is hands down, the hardest of all the phases I have experienced.
As far as being or not being her friend in all this, I have mentioned before ... for me.. not possible, not only do I not keep friends who lie and cheat, I honestly could not be a friend to my MLCr as I was to vested and biased for my own personal gain (or in this case loss). I had to go about as NC as one can with children for my own sanity and healing, I have finally arrived at the point talking to her is like talking to a co-worker I do not really care for ... I keep it professional and short and go about my day.
Hang in there, it does not go away but it does get better.