Admitting My Secret Kink

I've been married to my husband for five years now and we have a four-year-old daughter. We're happy but I feel like there's something missing in our sex life lately. It started when I was at home alone with her one afternoon, playing dress-up. She put on an old police hat and pretended to arrest me. The way she acted, so authoritative and bossy, made my heart race. I couldn't stop thinking about it later that night. We're usually very affectionate but this feeling of being dominated by someone felt different. It scared me too because I love my husband so much. So I didn't say anything at first. But one day we were watching a show where the main character was in a strict BDSM relationship with her partner and it clicked for me. That's what had been missing. The idea of surrendering control, being disciplined like that child had made me feel...I can hardly describe it. It makes my skin tingle now thinking about how she looked at me. So last week we sat down and I told him everything, well almost. I just said I wanted to explore some roleplay stuff with a dominant partner and see where it goes but he got quiet. His face was unreadable. We agreed to look into classes on healthy communication and boundaries for couples interested in that kind of play. But even as we did that research together over the past few days, I feel ashamed every time my mind wanders back to those moments with our daughter, pretending to be her prisoner. Is this a terrible thing to think about? How do you get over feelings like this when they make you question your marriage and yourself?