Complications of Creative Freedom in an Open Relationship

I've been with Lisa for five years now. We're both artists and have always valued our creative freedom. Part of that was agreeing to the open relationship, which meant we were free to explore outside our primary bond as long as it didn't interfere with us emotionally or professionally. The catch? It's not a written-in-stone rule; if either of us feels it's straining the relationship, communication is key. Recently, I started working closely with Alex on a large mural project downtown. She’s been in the scene for about three years and brings an energy to art that I find exhilarating. We connected over our shared passion for public murals and street art. It was inevitable that we'd start flirting; there's something about paint and creativity that makes boundaries blurry. I did my best to keep it professional at first, but the lines blurred as we worked together longer. She began showing up unannounced with coffee and snacks, and soon enough, it became a habit. One day, I was in her studio looking at some of her sketches when she walked in, wearing nothing but an apron that barely covered anything. We talked about our work but ended up touching each other more than usual, eventually leading to more intimate moments. It’s been weeks now and every time we're together there's a magnetic pull between us. I’ve found myself thinking about her constantly when I’m with Lisa; comparing everything, how she laughs, how she moves, and it’s starting to feel like something more than just artistry connecting us. The thing is, Alex knows Lisa as my partner, but has no idea we're open. This feels wrong on so many levels. I told myself initially that this was about the creative process and nothing else, but that’s not true anymore. There's a part of me that wants to explore this further despite knowing it could hurt everyone involved. It's like I'm trapped in this paradox where my passion for art leads directly into forbidden territory. So here’s the tangent: isn’t there something poetic about how our greatest creative moments come from breaking societal norms? Yet, every time Alex leaves after one of these sessions, guilt crashes over me and all that remains is the residue of a moment that feels both liberating and destructive. I'm stuck in this emotional limbo where artistry meets infidelity, wondering if there's any way to salvage what we have without throwing everything away.