Thanks everyone. I won't reply individually just now, but know I've read all your comments and appreciate every one.
Today's been a bit of a trial. I took my boy to his club this morning and, sure enough, the OM was there. My blood was boiling this time (it's not the first time we've crossed paths, as most of you will know) but I kept my cool, even when he was conversing with my son - one thing I've not mentioned previously is the OM is an instructor at my son's club. The thought did occur to me that maybe the club wouldn't be best pleased if they knew he'd used his and my kid to get close to my WW - then again, that's as if my WW didn't play her part. She more than did.
My wife was at work while I was there - often I pick her up on the way but today she couldn't finish early. At least for once I knew where the two of them were (or rather that they weren't together).
I had to go outside after an hour or so of pent up frustration, get some fresh air and find someone to vent at. I chose my mother-in-law. I know, against the 180 'rules' but I have a brilliant relationship with my in-laws and couldn't call my own mother as she has a house full, making conversation difficult.
I was outside longer than intended and when I went back in, my boy had been upset as I been gone a while. I felt mortified - all the more so as the OM had obviously taken the opportunity to step in. I made it up with my son - he understood and I apologised. I had told him where I was - but he's 5... I was in the wrong, and I felt pretty bad.
On the way home my wife text saying something like, 'how did he get on?', meaning our DS. I didn't reply as he had actually won a trophy, and he wanted to surprise her. She then called demanding, 'why aren't you answering my texts?'. Seems she doesn't like being left in the dark at the moment, even for a few minutes.
When I got in, she told our son she wanted to talk to me (that's a first, I thought). Turns out the OM had text her to spill the beans about my bad parenting, embellishing the story to say I'd apparently gone outside to see some woman!!!!!! And, of course, my wife took this as Gospel. I couldn't believe what I was hearing. Why the hell should my wife care, even if his lie were true?!?
So, we ended up in that conversation I said we wouldn't have today.
She repeated that she loves him, can't give either of us up, thinks now I have told my parents there's no way forward (!) and 'had' to see him today. Oh, and that old chestnut again (see a couple of Saturdays ago) - 'I think I'm going to stay out tonight' (she had a long-standing evening at the theatre planned with her mum).
She also made out again that today was the day she was going to go.
I put my foot down and made it quite clear what was going to happen if she so much as saw him today. Just like that other Saturday, she backed down and made a plan to come home by train after the play. Of course, last time, she found time to pop round the OM's for more sex, before coming home to me.
I let my mother-in-law know my wife now knew we had spoken - and filled her in on my WW's 'threats' to stay out all night.
So, here I find myself, home alone, wondering if my WW will somehow manage to be unfaithful to me again, despite the lack of a car this time and the tight timeframe between end of show and last train home. I'm sure it's quite possible.
Before you say it, I do KNOW she's with her mum and where she said she would be as I dropped her into the city to meet her, and saw her meet her mum with my own eyes.
Yes, more act and react (thanks, by the way, Bigger). I'm desperate to break this cycle too.
But before you point out the error of my ways/futility of talking to her AT ALL, please remember I AM seeing a solicitor on Monday morning, and plan on making the absolute most out of my free 30 minutes (your suggestions very welcome).