If I remember correctly the uke confessed to the seme within the first chapter, but was rejected. It is revealed that it isn't the first time the uke confessed. Later on in the story it's discovered that the seme had sent a letter of confession to the uke but the uke didn't get it until three years later, the time it was now. The seme kept on rejecting the uke because he thought that the uke was mocking him. Please give the name if you have any idea what it is called.

Time Lag? https://www.mangaupdates.com/series.html?id=1351

Thanks, i was looking for it too!))