New-ish (6 months ish) neighbour has a BF visit every few days; we know bcs we can hear their noisy sex 
Wouldn't care but it's so noisy (mostly her, really performative noises, can sometimes hear him too) she's woken our DD9, so AIBU to let her know? I'd be mortified if it were me but I don't know her well so have no idea how she'd react.
We live in a semi-detached, and we're usually in our living room in the evenings which is where we can hear her from. It's not so bad if we've got the TV in but on those nights we're just having a quiet one (working/reading/no TV) it's really intrusive. Mostly fed up with them waking our DD tbh, esp on school nights. She has 3 young DDs of her own, think they stay away when her BF is there as otherwise god knows how they sleep through that din! So; AIBU to let her know, in the hope she'll be a bit quieter, if only during the week? Or am I being U and should just put up with it?