My Partner's Boundaries Were Pushed Too Far During A Session

I've been a personal trainer for about five years now. Recently, I started seeing someone who is in an open relationship. We had talked about exploring some light BDSM during our sessions together, and she seemed comfortable with it. She mentioned once that bondage was something she'd be interested in trying but needed to know where my limits were as well. One day, we decided to experiment a bit more than usual. I thought we would just start with some gentle ties using silk scarves as restraints. But during the session, things escalated faster than expected. I felt a rush of adrenaline and wanted to push her boundaries further, thinking she was okay with it. But when we finished, she seemed distant and uncomfortable. Over dinner that night, she told me how out of place she had felt when I crossed into territory she hadn't agreed upon. She said the experience had left her questioning our dynamic. I feel so ashamed. It's clear now that while she is open to exploring kinks with a partner, it needs to be more carefully defined and communicated than what happened between us. We've since spoken about setting strict guidelines for future sessions but this incident still hangs over me.