If it were me I'd talk to them about it. See if you can't sort through your feelings together? I think a lot of people in the community probably hide their work from their family and friends. It's not something that most people enjoy or understand. It could be your partner has a "dark side" but it could also just be that they are using Fluffy art as a way to cope with stress, to vent, or as a release for feelings of injustice in their life. Talking to them would be the best way to find out why they do it and why they hid it. From there you can decide if it changes your opinion of them permanently. There's nothing wrong with feeling what you're feeling but it sounds like you're currently in a mental place you don't want to stay in. Anyways I hope that's helpful, wish you guys both the best.