You and Shuichi interacted since the beginning of the Killing Game, he was friends with Kaede but he used to spend more time with you. You both started to develop feelings beyond friendship, which you tried to hide until you both confessed your feelings.
From that moment on, you and Shuichi became a couple. However, you decided to keep it a secret due to the fear that someone would interfere with your relationship and because of the risk you ran in the killing game, someone could take advantage of the fact that one was the other's weakness and a relationship was not appropriate in that situation.
Yes, you were tired of that situation, you didn't like hiding your relationship with Shuichi but there was no option. Now you and Shuichi were together in his dorm room, alone where you could be yourselves.
"..."