It's really interesting to read everyone's responses here - no-one speaks fondly of the experience, and no-one seems to have acted out maliciousness or spite towards the wife.
My experience as the OW obliterated life as I knew it. Same old story - We met at work- I was young, in an unhappy, unfulfilling relationship; he was older, senior, married with 3 kids (his second marriage). He charmed me, seduced me, swept me off my feet with affection and attention, told me he was desperately unhappy in his marriage. We had what I would call a 'rip-roaring' emotional affair for a few months before eventually it became sexual.
The only difference in this story is that he very quickly started saying he would leave his wife for me - I literally begged him not to be so stupid - but he did. One day, after just a few months, he actually left her- for me.
Was I the devious, triumphant 'other woman'? No - I was shit scared and literally went numb with shock. I felt because he'd done such a massive thing for me then I owed it to him to leave my partner too. What followed was 2 years of hell - he turned out he was hugely emotional abusive and controlling. I'm pretty sure he cheated on me - and his wife went utterly crazy from his lies. I felt so so guilty, and in pain - and pretty much everyone in my life turned against me for what i'd done. Eventually i left him - he literally stalked me for months before one day switching off - I think he found his next victim.
2 years on, I'm still recovering from the most terrible, confusing, horrendous time of my life. I needed therapy for the first year. I went through absolute hell - but not one day did I not think about his wife and how it must have been 100 times worse for her. I feel so bad for her, and hope she found happiness in the end.