Last thread.
www.mumsnet.com/Talk/relationships/3998907-I-think-this-it-the-end
Ex had been gone 7 weeks (4 at his mates and the last 2 in his new rented house). Dropped the kids back to me after having them for tea and told me "Since I got my new place I've been spending time with a friend, and we've been out a few times, so I wanted to let you know myself before anyone else did." Apparently a friend he's known "a few years".
I cried and asked him to leave. 😢 DS1 came down as he heard me crying, and also cried (I told him as he's terrified of covid at the mo and I could see him start to freak out wondering why I was so upset). He's now refusing to talk to ex.
The next day I asked him WHO it was, and it's someone he's known a long time, and who I felt uneasy/suspicious about during lockdown as she was commenting on his runs and I noticed he was clearly chuffed and revelling in her comments.
I pushed my uneasy feeling aside, told myself not to worry, that he'd never do anything, etc.
He's still adament nothing happened. 
I'm gutted. It really floored me him telling me. For me that means the door is locked and bolted. There was a miniscule chance that I figured way down the line he might grow up, stop being a twat etc and we'd maybe reconcile. I knew it likely would never happen but it was a miniscule possibility. Now it will never happen.
In a way its helped. I know for certain now that:
- the night he didn't come home he was likely with her
- he's a liar
- my instincts that I pushed aside were right
- I was right that he was looking for an out
- mners and I were right that he likely wanted to scope the possibility of her by having a few weeks at his mates house
- I was right to decide when he floated the idea of a few weeks at his mates to make it a permanent move.