Yes
Stupidly I let him
Made a "huge mistake" he said, "I was and will always be the love of his life" and many other such platitudes, blah, blah, blah!
Month in from discovery, I found a card from him to her, along with his scribblings of asset division, pension calculations etc. Had I not discovered this our joint account would be very much lighter as he was planning to use the funds for a deposit on another property.
His new found commitment to me was Oscar worthy!
My life then turned into a living hell as he refused to move out again ,(she not being ready at the other end). One night he took his frustrations out on me when very drunk and I ended up in casualty with a broken nose. That was the leverage to remove him.
Wished I had MN back then.
I do want to be happier than he is though - it sounds silly but it's just how I feel. I hate the thought that those two could be happy together when they caused me so much hurt.
T & C ,Agree, your day will come. FWIW I saw ex and ow in town together, they have morphed into the teletubbies, comfort eating/drinking, he in particular looks bloated and old and not very happy. Did my spirits a world of good 
Waves to WHK keep on keeping on, you will get there. hugs