Started seeing my supervisor and now he is pulling away?

me and my supervisor started seeing each other however we have kept it a secret as our work has a big no dating policy. We have decided to wait until the end of the month to start seeing each other more seriously as I will be leaving our workplace, however we still flirt and sometimes I sleep over at his house, we were acting as if we were dating without the labels we both agreed to be exclusive and not talk to anyone else. However recently we had a conversation on how he has been pulling away a bit and he told me he is nervous about our workplace finding out and after I leave things will be different. Since that conversation we have not been talking and we have not worked together. He has been flirting way less than usual and does not ask me to come over anymore, however I am not sure what brought on this weird behaviour from him.

Started seeing my supervisor and now he is pulling away?
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