I'm confused🤷‍♀️

So I've been with my current boyfriend for almost four years and I really really love him. However, I can't help but feel like our relationship is taking its toll. I mean every relationship has its ups and downs but I'm only 20 and I feel like he's sort of holding me back but at the same time it's so comforting to be in his arms. And we still have a really great relationship but I can't help but think maybe it's not what I want anymore. Then there is this other guy that I've known has had a crush on me for a very long time and he makes me feel special (something my boyfriend very rarely does). I feel so so guilty for talking to this guy while I'm with my boyfriend even though we haven't done anything I still feel so guilty for talking to him behind my boyfriends back cuz I know he would never do anything like that to me. Should I feel bad? Is it possible I could be falling out of love with my boyfriend? I can't possibly think about leaving him for someone else because it would break his heart and mine, but I can't stop thinking about this other guy🤦‍♀️