In the latest update, there seems to be a problem with the daily interactions. I was only able to engage in either dating or sex once. After that the buttons became unresponsive despite several in-game days passing. It's as if the once per day limit never recharged after the day ended.

You might be using a save from earlier version which can cause such issue because of a new upgrade

Works  fine   (mult fresh restarts)   v  5.1a