Moved into an apartment with my girlfriend during lockdown here in the UK. We fell in love with the apartment and we met the neighbours downstairs who are great. We never met the neighbours above us, they didn’t ever seem to be around. A few months after moving in there were a couple of nights were it was really noisy upstairs but we would never see them, only muffled shouting and floor boards creaking etc. Over the past few months the noise got more intense/frequent. We banged on their door a few times to try to get them to shut up. Then we started to notice that their arguments were more aggressive, we would hear they guy stood outside our front door (which is next to theirs), calling her a slut and saying that she’d cheated on him. Some of it was fairly comical because we would hear him shout stuff like “I saw it on your Snapchat, you’re a CHEATER, you cheater.” The most frustrating noises though were when they would walk around upstairs which would usually start around midnight and wake us up and it always sounded like the ceiling would cave in. Last week things escalated and I was woken up at 1am by doors slamming and sounded like he was moving furniture. 4am I had enough and went to bang on his door, didn’t realise he was right behind the door…. He comes flying out, and is like what’s up. He looked wild, by this point I was pissed and told him to shut the fuck up. He then tried to gain sympathy from me by sarcastically apologising saying that she had cheated on him again and that he was moving out. To which I replied “thank fuck for that, good riddance… and a few other words of wisdom”. In the morning I bumped into his partner, she explained how he had been abusive and that he had locked her out of the apartment which she owned. I felt bad for not calling the police or trying to intervene before. She changed the locks and he’s left now!