The choices decide if you see the true or bad ends. There's a point system in-game. Get below a certain score and you get the bad end. And there's no issue in Daichi's desires. Its just that he became involved with the wrong person. I wish I could explain more, but we'd be entering spoiler territory in things that I have planned. Just...grin and bear the pain for now. Once all the arcs are out, it'll make sense why things ended the way they did and maybe you'll get that happy ending you want.