Progressive women…please help me understand this?

My gf and I work out at the same gym. Yesterday, I was on an elliptical machine, and I could see her and the rest of her female aerobics cl just dancing away. It was an incredible turn on…When we got back home, I was overwhelmed with the urge to take a whiff of her undies in her gym bag…This put me over the edge, and I wanted to pounce on her. She called me a “freak.” I was just being myself. What do you think?