It started when he was defeated by Gu Yuena during the Joust For A Spouse Festival back then. At the time, he realized that he could not possibly be with Gu Yuena for the time being. He had no idea why Gu Yuena would do that to him. Despite knowing full well that she loved him, he knew that he could not win her heart at that point regardless of what he did.
The feeling was agonizing. In fact, he would even describe her as being ruthless. As a result, Tang Wulin refused to accept it all this time.
In any case, he had far too many things to deal with in his life. He needed to elevate his cultivation base, manage Shrek Academy and the Tang Sect, fight against the Spirit Pagoda, confront the military, et cetera. Everything needed his full concentration and effort.
He did not have the time for himself at all. Moreover, he was well aware that there was nothing he could do in the time being.