Back in 2010 I was living in the US. Had moved there 7 years earlier to be with my now ex when I was 18. Given up everything, family, friends, career, and moved halfway around the world. Not at all still bitter.....
I was flying home to visit my family, he dropped me off at the airport in MY car. I landed in Bristol Airport 12 or so hours later, wasn't even through passport control when I checked my voicemail - he'd been arrested and needed my help. Managed to get hold of him, he's in tears saying he stopped for a beer on the way home from dropping me off at the airport and got pulled over for a DUI. I needed someone to bail him out, by this point he's sobbing and as angry as I was about him being arrested I actually felt bad for him.
I go straight through to check in, buy another ticket, and back I go on the same damn plane I just got off. Don't ask me why - I was stupid and thought he needed my help.
Get back to the US, go to the jail to bail him out, find out that he wasn't alone and that wasn't the whole story, but the short version was his OW was in the car with him when he was pulled over.
I never saw him again. I packed what I could into a suitcase and came back for good. He did briefly try to reconnect with me earlier this year to apologise (only took nearly 10 years to feel remorseful) but turns out he got married to someone less than a year after I left (not the same one he was with the night he got arrested) so no idea if there was another one on the go too.
I still feel such a fool all these years on and haven't really let anyone else get close enough :(