How old are you? Can you give us more background please, has anything accured that has you second guessing?

My advice would be to take a break from the relationship, your clearly confused, do you love him? Or are you afraid of being alone? I myself had this very issue with a long time ex.

I'm 16 and have been with my boyfriend for 3 months and I just feel like I'm being smothered.
And there's this other guy that I have been friends with for a while and I like him, but I don't know if I feel smothered because I want something different or because its time to move on.
My boyfriend says he love's me, like he's madly in love with me, but I just don't feel like I used to and I don't want to hurt him.

Yea give it a break, get some time to yourself and think about your relationship.
If there's no love between you two then the best for both will totally be the break up and a search for new partners.
Just give yourself some time.

You may as well learn at your tender young age to be honest with those that love you as you would want the ones you love to be honest with you.

Yes it will hurt, but not as much as leading them on with a lie.