Caught Between Art and Love

I've been with Sarah for three years now. We met at a local art show where I was selling some of my work. She's an accountant, nothing creative or colorful about her life, but we clicked over our shared love for the arts. We're happy together, but there's this one thing that keeps me up at night. I've always had a fascination with taboo fantasies involving roleplay and power dynamics, not anything illegal, just adult stuff that pushes boundaries. I never really got into it deep until about six months ago when I stumbled upon some art online that rekindled my interest. I started sketching scenes in private notebooks, trying to keep it from Sarah. But the urge grew stronger as time passed. It's not like I want to hurt anyone or make her uncomfortable; far from it. She has no idea about any of this, and part of me is terrified she'd leave if she found out. But another part feels trapped in a lie that keeps growing bigger. A few weeks ago, we went on a weekend trip where the hotel room was quite private. The moment I stepped into our cozy space away from home, I felt something stirring inside me. It's not like I could just spring this fantasy out of nowhere; we both have an unspoken agreement to keep things vanilla in bed. Yet there it was, a seed planted by my imagination during that quiet weekend. Since then, the questions and doubts have been relentless: Is this a phase? Am I being unfair hiding who I truly am from her? I care deeply for Sarah but can't shake off these urges either. What should I do? Have others faced something similar where they wanted to share their fantasies with someone but feared rejection?