Never sad, only excited. Before we got married I used to watch her and her various boyfriends from my 3rd floor window, it has a courtyard view and if she left the drapes open I could see the bed and her in it. I used to watch her getting fucked and stroke off to the scene. Half the time I'd swear she knew I was watching.
Finally I went down and knocked on her door on time about 20 minutes after a fellow left, she answered, I invited her for coffee. She smiled and said she just made some and invited me in. We talked and drank coffee until the dawn, then made love. I was aware she had sex hours before and yes I could tell but it was magic.
For the best year then I know she knew I was watching, I'd come down after the other man left, sometimes she would clean up, other times she'd leave it wet and sloppy. We fell in love over the course of that year and I married her almost a year to the day of that first time
So when I watch her now I have a closer feelings for her and enjoy it all the more