I've been 5 years in a relationship and I'm not in love with this person anymore. They adore me .. how do i handle this ?

It is important to place yourself in the other person's shoes. Would you want to spend another five years or longer with someone who didn't love you? Empathy is something that can be lost in long-term relationships as couples settle into "cruise control." It's a good idea to routinely consider the other person's viewpoint, not just about short-term decisions (i.e. what to make/eat for dinner) but long-term decisions. Mindfulness about the proportionality of feelings between partners is also helpful. Pop culture versions of couples depict emotional check-ins as adversarial or contentious. They don't need to be if both people are open, honest, and thinking about the best interests of both sides.

It would be best to just rip the band-aid off. The longer you take the more it will hurt the both of you. Sit down with them and talk. It will be a heavy conversation but you have to do it for your sake and theirs too. Let them know you've grown out of the relationship, they deserve to know it. It is very difficult and requires courage and they will be hurt. But they will heal and so will you. Dragging on a relationship does no one any good. This is only if you want to get out of the relationship.