Read between the lines, mates. The very first response to the OP was from a man, who asked him perfectly politely several times about counselling and mentioned mediation. This was completely ignored by the OP.
He then said the wife is sick of the kids, but when asked if that meant she was talking about leaving them with him, again he didn't reply. My guess is, because it isn't true.
Several posters did offer quite kindly advice, too. But he was too busy arguing with the ones who didn't, to read or acknowledge those.
OK, my views are unavoidably coloured by my own experience. I can only say, I too had a manipulative bloke who didn't listen and refused to go to counselling until I had told him we were definitely over. He didn't take it seriously either until the solicitor's letter plopped on the mat. (The letter was addressed to him, mind you; if I'd caught him opening my letters I'd have cut his hands off. But I had all sensitive correspondence sent to a different address just in case, and I strongly recommend anyone in this position does the same.) He also threatened to post on Mumsnet, and even to get an account and join my online computer game, but fortunately his technophobia was stronger than his desire to invade my space. Make no mistake, he wouldn't have had any interest at all in Mumsnet if I wasn't on it. He would stand behind me and watch and make comments about various of the posters as if they were his best friends, then laugh when I minimised it. And of course he too said I was "deserting the family" - even the children believed it for a while.
See, we've seen it. Like the abusers' script and the cheating spouse's script, we've read the about-to-be-left partner's script and this OP is a classic. That's why he got short shrift from some posters, and why the ones who offered him the best practical advice were nevertheless fairly sure he wouldn't take it. And it's why he's huffed off now.