Maid peeps on us having sex.

I was having sex with my girlfriend and suddenly I noticed my housemaid's shadow that confirmed she is peeping on us.

To my surprise it was arousing for me. Giving it a thought I realised that she naturally knows what we do in our bedroom and we both are comfortable doing it while the maid is at home.

yesterday was the maids birthday and my girlfriend insisted on gifting something to her. Our maid is a nice girl and she is excellent with work too so I agreed. she gifted her a dress and bought a watch for me to gift her.
The maid hugged me and hugged my girlfriend and kissed her cheek when we surprised her. I didn't feel anything weird about her hug because she did the same to my girlfriend.

Only weird thing is that she watches us having sex but it's becoming pleasant for me. is it normal that I like her do that?