Ryou deserves a lot of respect not only did he present himself as the bad guy to help natsuki be seen in a better light, but he also tried to end it once he realized natsuki had a lover. He deserves happiness.
Also, am I the only one who things this will never be truly forgotten or forgiven for both of them?
Did it ever say where his debt came from?
yes they did in last chapter or the chapter before it I think
His dad was a gambling addict who borrowed from the loansharks. It was like one throwaway line, not that important.