Is OTHER wrong in the post ? POST :  

Throw-away account. English is not my first language so please excuse the grammar.

My husband and I have been married for 12 years and we have two young daughters. We've had a good marriage overall. The last year, I've been struggling personally.

After a three month dry-spell, my husband asked me to either go to couples counselling or pursue an open marriage. I was tired and down on myself and in that fog, I agreed on to an open marriage. I felt so undesirable and so off-putting that it made sense to me to allow my husband to pursue another woman. Despite my reservations, I went along with it with a few agreed upon ground rules:

1 - he must use condoms. Not any sort of other protection (he's had a vasectomy), but condoms because I am a mom and I don't want anything to jeopardize my health (or his)

2- cannot be away for more than 2 nights per week and can't infringe on family time

3 - cannot develop feelings for other person or must stop relationship

4 - any one partner can veto this arrangement and we go back to the way things were without any judgement or resentment

5 - cannot expose our kids to this and must be held private and not disclosed to family or friends

So, my husband disclosed to me that he will be pursuing a 23 y/o co-worker who works long hours and doesn't want a relationship.

He started working out as well, and they would actually sometimes go to the gym together before work. He was more energetic, a more focused dad, and more present at home when he was here. 

Until one day, I had a migraine headache at work, and I left early and accidentally walked in on them having sex. And, the sight of it was one of the most revolting things I ever had to witness with my own eyes.

I freaked out, started to cry and ran out of there. But,I also did notice that he wasn't wearing a condom. And, I also learned that he violated a few of our other rules, because he was actually seeing her a lot more often - they saw each other during lunch breaks, before work, and probably saw each 2 to 4 times per week and not 1 or 2.

He told me that if I was fine with it before finding out those things, and that I was the one who gave up on the marriage in the first place by agreeing to the open marriage rather than therapy. He told me that the girlfriend is interviewing for jobs hundreds of kilometers away, and it will be a matter of time before things fizzle out naturally, so why not let it end and we can go back and work on our marriage. 

Then I realized that my husband basically couldn't tolerate a three month dry spell, and when I was at my lowest, presented this twisted deal to me and I agreed. I asked for a divorce, and he thinks I'm being an unreasonable asshole.

He broke the rules, so all bets are off, and I essentially have PTSD after this experience. AITA?