How long did it take your partner to fall in love?

My boyfriend says he loves me. But that he isn't in love with me, and he knows I'm falling in love, but that he's not, and he's not head over heels. We've been together for over a year now. I'm not sure what to think. Everyone loves at different paces. But he expressed how we got comfortable with eachother so fast. And that kinda worked against us. I wish that he could be in love. It kinda hurts. He says he doesn't want to lead me on into thinking he's going to be with me now and forever, and isn't sure where life will take us, and if he'll want someone else in between. I totally get that because we're both in our early 20s. I don't need a forever promise, I'm not trying to live in La la land. I just thought he loved me more than he recently admitted. How long did it take for your partner to be in love?