And then, as I now began to perceive (I had at first thought otherwise), he was for the first time in his life experiencing something deeper and more confusing than his customary animal passions.

He may at first have wanted Marie Ivanovna as he wanted his dinner or his supper ...

now he wanted her differently.

New emotions, surprising confusing emotions stirred in him.

At least that is how I interpret the uneasiness, the hesitation, which I now seemed to perceive in him.