My wife is way more into this than i am. am i being dragged into something

kinda need to type this out somewhere thats not my own head. m38, wife 36, 11 yrs together. she brought up the LS about 18 months ago, way out of left field for me, and ive been slowly getting on board ever since. i thought i was on board. like genuinely thought we were on the same page and we were doing this together at the same pace. then last weekend she casually mentioned she's been messaging a couple for like 3 weeks without telling me. nothing crossed lines, no pics, no plans, just chatting. but the fact that she was doing it independently and didnt mention it kinda... made me look at the whole thing different. she's reading the books. she's on the forums (lurking, she swears she doesnt post, but lurking). she's the one who picks out the lingerie and books the hotel rooms for our "practice" weekends away. im just kinda... going where the train is going. now im sat here wondering if i actually want any of this or if ive been quietly nodding along bc she lit up the first time we talked about it and i didnt wanna be the guy who killed the spark. how do you tell the difference between "im enthusiastic-but-slower" and "im not actually a willing participant"? bc i love her, i want her happy, i find some of this stuff genuinely hot in theory. but the asymmetry is starting to weigh on me.