I have a new relationship with someone I've been friends with for a while. This person is reserved has taken a long time to be open about who they are and what they enjoy.

I've known they've had a partner since before I met them. Over the time of me getting to know them, I've learned more about their relationship. Specifically, that they have an ongoing BDSM dynamic. I've recently learned that this dynamic is more involved then I feel I was originally led to believe. Video Recordings, D/s dynamic, etc.

I don't really want to know details of their relationship, but I feel some of these points are pretty big and I should have been told so I could choose if I wanted to be in the relationship with someone who had these types of dynamics in play. I'm wonder is that fair of me to expect?