My DP of 5 years broke up with me in late January. Because of work and childcare reasons, we live just over an hour apart in different cities, but had what I thought was a strong, loving relationship.
Looking back he'd been distant for quite a few weeks, but I was going through a terrible time over Christmas and into January and hadn't really had time to give it much thought. My mum was in hospital over Christmas and died in early January. My DP came to stay with me for a few days after that (last time I saw him) and then 2 weeks later broke up with me.
I'd confronted him about what was going on because he was not being chatty on calls etc, was hard to get hold of. Basically at a time when he should have been supporting me he was pretty absent. He said he was finding the living apart difficult, that our lives were too different etc (I have kids he doesn't, for example) and ultimately that we needed to break up. Got really mad when I asked if there was anyone else and has consistently maintained since that he's not looking for anyone. (After not talking for a month, he'd been sending friendly messages. I shouldn't have engaged with them, but I was open to potentially trying to work things out so I was up for chatting a little 
).
Anyway, back in those first few weeks after the break up I was desperate for answers. He's part of a Facebook social group in his city that organised meet ups. I knew he'd been going to their regular get together on a Friday night and it was around that time he'd started acting odd. So I created a second account and joined the group chat. I've never joined in the chat, just lurked on it for a few days and then just stopped looking at it as I knew it wasn't healthy or a good use of my time.
Fast forward to yesterday. I never shut down my laptop and was closing a load of open chrome tabs and the chat is on one of them. And low and behold someone's talking about my ex and a woman in the chat always 'getting it on' at the Friday night get togethers. From what was said it's clear this was back at the end of last year/start of this year when we were still together and it now appears that they're a couple. I just saw red. I posted in the chat who I was, that we were together 5 years, that we broke up on x date and that this was all going on whilst my mother was dying. I've also messaged him telling him what a disgusting human being he is.
This morning I feel so sick and shaken by my actions on the chat. I know he's going to paint me as this crazy, psycho ex stalking him online (and tbf I do feel really shit about getting into the group on false pretences). I was just driven by this feeling of 'why should he get away with this? Why shouldn't she and everyone else in that group know who he really is?' I'm normally a very private person who'd run away from online drama, but I just couldn't help myself in the moment.
I'm also feeling so broken. The man I thought loved me (and was telling me he still loved me) is a liar and a cheat. He'd been making out that the split was hard for him too, that he wasn't looking for anyone else, that he'd never feel for anyone like he felt for me etc etc. I feel like the person I loved didn't exist. I can't get over how he the man I loved could behave like this and treat me in such a disrespectful way. Maybe I should have held on to my dignity yesterday and just cut contact with him and not messaged the chat. But why should he get to walk away and not be held accountable?
Sorry that's so long and rambling. Just need to get it all out.