Why a man would block a woman right after having intimacy, and after pursuing her himself first?

I know this man in his early 30s with whom we always had strong chemistry but nothing came out of it as we both are unavailable for relationship. However, time to time he reaches me out and wants to meet. Normally i dont but this time I agreed(not the first time though). All went fine but it was clear as always that nothing more will come out of it because of our unavailability for something real.

He blocked me the next day. Why? Any ideas?