Should I just end it?

So me and my boyfriend have been dating for a little over a year. I love him but I’m honestly just starting to loose feelings. I’ve been becoming attracted to other guys again and I just don’t feel all the butterflies and fun, and excitement as I used to. I honestly haven’t even felt extremely sexually attracted to him also. I just haven’t really wanted to have sex or anything. I just don’t know if I should end it or not. I don’t think I want to, the thought of not having him breaks my heart but he’s really just starting to feel like a best friend to me. I just don’t feel like I used to. I don’t know what to do