Yes, I don't get that either, for now. Why would Lucrezia start being that enterprising? That's not how we're used to see her behave with him. Her solace, her love... that he was, always. But I would have never imagined she would have the upper hand in their relationship. I think I'm just as curious as you when it comes to that matter!
I have a few theories but they are all probably way off. Maybe Alfonso sees Cesare watching them and that combined with other things he sees, makes him confront Lucrezia about her relationship with her brother. Which in turn makes her question it as well and begin to see Cesare in a new light, a more sexual light . Or maybe Alfonso doesn’t satisfy her and she comes to the conclusion that only a Borgia can. My last theory is the one I like the least and it’s that playing off of what she said last season “pity was he loved a Borgia” in regards to Paolo’s death. Maybe her father/brother’s political interests start to shift away from the alliance formed from her marriage to Alfonso and she starts to sense that his life is threatened. Therefore causing her to realize “only a Borgia can truly love a Borgia” and being who she is she will never have a happy fairytale marriage. Those are just my theories though they are probably all completely wrong.
