Most people don't even notice the little things their partner does every day. It doesn't really matter whether she's at the gym every other day for precisely two hours - all that matters is that she comes home. She doesn't care if you're going for a drink after work, only that you'll pick up some Thai food on the way home.
Sometimes, though, she will start to take a keen interest in what you're doing and where you'll be. That's not because she's suddenly fascinated by what your friends talked about over a couple of beers. Sorry. No, it's actually so she knows what she can get away with, and for how long. Basically, whether the bed's free for someone else. Might be time to shake up your routine.