First Boyfriend advice??? please help.?

Me and my boyfriend have been going out for a little over a year and he treats me wonderfuly and says im the one he wants to be with for awhile and does everything humanly possible to make me happy. He is my real first boyfriend and I am 17 and he is 20. Recently ive felt bored with him and not really sure if hes the one for me although I still love him to death. He is quite clingy and i have tried to tell him in the past that we need to take some time away from each other for awhile but he always guilt trips me back. im not really sure if i should leave him or not and if i do not really sure how to break up with him nicely please help