Not happy in my relationship. Advice ?

I’m not very happy in my relationship anymore. My bf and I have been together a little over 3 years now. I’m not very happy anymore. I just don’t feel the same love for him anymore. I still love him don’t get me wrong but it isn’t the die for you love. We are always arguing now and there is always something. I expressed to my bf that I’m not happy anymore and that sometimes I contemplate on breaking up. He told me that he really wants to make it work and that I’m his love of his life. He says that he never wants to lose me. Idk sometimes I just want to leave and be happy. But other times I want to stay. I really miss the love I had for my bf but I noticed it’s not the same. Like now I’m wondering if he’s the one or if there’s someone else better out there. I would never cheat on my bf but the thought of finding someone who LOVES me like the way I want to be love makes me crave that. Things with my bf haven’t been the same. I feel like things are being dragged. But he claims that he never loved me more than he does now.