I guess the way I see it Kuon is the real him and Ren is a construction that is maintained most of the time because he would rather have people see what he wants them to see rather than fix the side of himself he hates, he has buried his true self under a mask. She is like the only person he feels even slightly ok being Kuon around. Ultimately the Ren and Kuon personae's should be recombined, but I dont' think that Ren is the authentic him.
But the whole pretending to be a fairy came more from Kyouko than from him ya know. And yes he is using that personae for his own benefit but he is also using being "Ren the famous actor senpai who can do no wrong" personae to his own benefit as well.
I think her breaking his curse with a kiss would be good as it might help him start to forgive himself and drop the pretense. So kissing Ren would be just as much kissing a fake person as kissing a fairy, Ren is not real either. But that's my view of it, I get the way you guys that don't want them to kiss in a fake form see it, I just don't see it the same way.