Backstory: Wife(33) and I(31) rent a house with my brother (34) and share all bills evenly 3 ways. This has worked for us without issue for the past 2 years.
When we moved into this house, we had a 1yo child. We came to a mutual understanding that if he agreed to move in with us, that he’s going to be living with a kid and it wouldn’t be a frat house or anything crazy like that. Typical 9-5 work, come home, dinner, bath, bedtime routine during the weekdays and sleeping in on the weekends.
We had another child in Sept last year, and while it’s been a slight adjustment, it hasn’t changed the day to day by much. We told my brother we understand if he didn’t want to live with us anymore since we now have 2 kids, but he said he didn’t mind and enjoys living with us.
Fast forward to this past week: My brother recently met a girl at the gym about a month ago and asked to bring her home one night around bedtime. I let him know the kids were about to go down for bed and that I didn’t mind, but to just keep it down so they don’t wake them up. He said cool and that was that.
Apparently she’s been over almost every day the past week and I wouldn’t have noticed if we didn’t have a ring camera because they’ve been coming in after midnight when we’re all asleep, then leaving the next day when we’re either gone or sneaking out when we’re occupied. I don’t have an issue with this! Cool, you two have been quiet and not waking up the kids in the middle of the night. Appreciate it!
This past weekend she stayed the night again and around noon the next day my wife, kids and I are all hanging out in the living room just playing with toys when we hear the girl moaning so loud you could hear it throughout the house. It was so loud my 2(almost 3) year old was asking what was going on.
I got mad, went upstairs, and started making noise by opening and closing the washer/dryer just to let them know we can hear them. Went back downstairs and into the kitchen to do dishes. I was still fuming and figured they have to pass by the kitchen to leave the house and I knew they were going to leave soon since my brother had to go to work soon (he works at a restaurant so not the typical 9-5 workday).
When they came down is what prompts me to post here… I yelled at them both. “When we can hear you guys throughout the house, that’s a problem. When our kid is asking what that noise is, that’s a fucking problem.” Then I directed my attention to the girl, “Why don’t you go do that at your house and let your kids hear you guys?”
side note: my brother mentioned that she has a kid and is married BUT is in the process of separating right now.
I was mad, that was probably a low blow.. my brother called me later and said she was crying in her car and he wants me to apologize to her.
I do feel like I should apologize, but for a different reason. I shouldn’t have confronted them both the way I did… instead I should have talked to my brother privately… hindsight is 20/20 I guess… but like seriously, why was she being so loud mid day when we’re all at home on a Saturday?!
Anyway, I still agreed to give her an apology… but then the next day around midnight I was up in the kitchen making bottles for the baby when they walked in. I was prepared to apologize, but she walked straight upstairs while my brother stood at the base of the stairs looking confused. She texted him that “she’s not ready to see you yet and she needs some time to accept an apology from you”
Huh… okay well AITAH? kinda don’t want to give an apology at all now. Why am I apologizing about feeling uncomfortable in our living space? And I know it’s his living space too, but we never once told him he couldn’t have company over. We just don’t want to hear all that mid day when we’re playing with our kids in the living room 
