TheVoicesDoesn'tLikeYou wants James Sr/Harry and "Rebound continued".
James had, when he found Lily in bed with Padfoot, his best friend, acted a bit rashly, he would admit it. And he would also admit that he understood why Harry had said no when he kissed him (basically molested him, his conscience pointed out). He probably would have too, especially if it was someone he loved.
No, James understood exactly, because that was what he was supposed to be. The Rebound Guy. James was going to go out with him, not openly of course, fuck him a few times and then dump him, after feeling a bit better about himself.
But then James kissed Harry. And Harry kissed back. Now, James had had his fair share of kisses, many deeper than the one he'd shared with the other boy, and his fair share of more, less innocent, encounters also…
But none had done what this kiss did. This kiss had made lightning flash, stolen his breath, made his mind foggy and made his heart race. This kiss, this kiss seemed to touch his heart.
At this moment, anyone would have been able to walk up to James Potter, slug him in the nose and ask him about his crush on Lily Evans, and all he would have had to say would have been "Lily Evans? Who cares about her?".
James Potter was in love. With another boy. With Harrison Darcy. With someone he knew reciprocated. He was also walking on small pink clouds, but that had nothing with his newfound love to do, but rather the spell Frank Longbottom had sent at him when he rushed through the common room.