She used to stay over for a night or two every couple of weeks while she was growing up, I’d hardly call that a second home.

Even if it was this was a family barbecue not some college house party. It’s not appropriate to be slipping off to have sex regardless.

So does OP lol.

She went off and started having sex at a family gathering in someone else’s house

“She probably thought I was looking up NSFW material during my grandmas funeral”

Well I mean….that’s exactly what you were doing