Is he my Boyfriend or my Best Friend?

My boyfriend and i have been together for 4 years and lately we haven't really been having frequent . Last time 3 weeks went by without and sometimes i dont even want to have when he does. i love him dearly but i cant figure out if im just comfortably in love or if i just love him like a best friend and i can't admit it to myself. i dont want to hurt him because i know that he loves me. But wait theres more. . . i went to a party last saturday and met a man named harold who really infatuated me and i felt like i wanted to be near him and i wanted to be held by him. i felt pionate in the kind of way that i want to feel about my boyfriend. im very confused and i want to talk to harold more even if we never actually get together. i love my benjamin but it seems like the flame has gotten a little low on my side. the relationship that im in now is the longest that ive ever been in so i guess i need to know if this is natural or if theres something else! HELP!