Here’s another perspective: I was the OM.
She left her fiancé because she fell for me - I listened to her and encouraged her.
Fast forward ten years: we’re married, have kids, own our home and she still writes that I’m the love of her life in my birthday card.
Fast forward ten months - not even a year...
She’s in love with a guy she got chatting to at the school gates. He listens to her. He supports her. It’s the first time she’s felt like this. It’s Our Story from ten years with him recast as me.
As with you, there was nothing wrong with us - not in her eyes. The best she could say is motherhood had changed her so we were no longer compatible. Like it was a shared love of Meatloaf that held us together and now she’s not into it then it’s gone...
Truth be told, having obsessively sifted through the wreckage there is one thing that keeps poking out. And it the thing I see you and similar posters mention often. The OM listens. He’s supportive. And that’s not to say that I wasn’t. Even she acknowledges that. But life with a family is difficult. And as an H and W you have to look at stuff together that you really rather wouldn’t. When you have to point things out that you really rather wouldn’t - be they finances, the state of the house, kid’s wellbeing, etc. You are going to argue at times. That’s a given.
The OM doesn’t do that. I didn’t do that until we were married and had kids. They can blissfully sing their paramour’s praises all day, everyday.
Truth be told that’s why, in hindsight, I feel we were on rocky ground. I was always scared if I pointed out we didn’t have enough for that holiday or seemed anything less than her number one cheerleader she would get fed and go. So those issues never got fully aired. But the trouble is they didn’t go away, they just bubble up regardless - suddenly you have to look at that bank balance - and she reacted as she chose: what a bummer life is now. Here’s a guy who tells me that actually I’m wonderful, who looks up to me because is lot is even worse than my own and who I can escape from dealing with the messy stuff by becoming first time lovers again.
Don’t get me wrong, if someone’s in an abusive relationship or a partner refuses to change or is neglectful I fully sympathise if they leave for someone else. But these instances of “there’s nothing we with H but I’ve fallen for OM” do make me wonder, given my experience, if it boils down to a) I want to feel like a giddy teenager again and being in a marriage means I can’t or b) there’s the usual messy stuff that comes with being in a long term marriage and I don’t want to look at it, so I’ll start again with someone new.
Sorry, long post. I’m still working it out.