My Ex-Husband's Return

I recently got separated from my ex-husband after years of unhappy marriage. One day, we had a surprise visit from him, and he seemed to have changed, more confident, more appealing somehow. We ended up at his place, where the tension was palpable. I found myself drawn into his embrace, despite all our issues. He proposed an arrangement for us to explore old desires, and I agreed. Afterwards, we parted ways with a mutual understanding that it won't change anything but felt there might be more unresolved feelings between us. Am I just being foolish or is this normal after separation?