I also am in agreement with Mag & Rp on the NRE/infatuation thing. If it weren't so scary you could sit back and enjoy how cute it is and have a good chuckle
Don't worry - it will pass - just like yours did.
But beyond that, I think I'd downplay the whole "love someone more than another" thing. Yea, it sounds scary. But I don't think it's exactly accurate ! Love "volume" (more or less than...) is kind of a shadow world. Not quite real in most cases. And what little of it that may be real is VERY situational and transient in my experience. It may change completely in an hour, month, day etc Dependant on the circumstances in your face.
And even more than that, I have a suspicion that the 'words' aren't necessarily conveying the true meaning he's trying to express. Because likely he doesn't understand it yet either. This is new territory for so many people. And even though we step into new territory, we bring our old tools & methods (including language) with us to try to navigate.
What he's experiencing is a NEW love, maybe a new TYPE of love and it's all like a new toy or new ice cream. It's WONDERFUL ! Overwhelming. Confusing. But it is definitely one thing. INTENSE :0 It always is. That intensity of course 'could' be described as 'more' - based on it's current level of intensity. No doubt it existed at that level in the beginning between you two also. But like fine wine, it mellows. It loses some of that intensity (temporarily) and mellows into something fine and dependable.
So let him open the new bottle. Let it blow him away. No harm done. It's not 'more' - only different, heady.
See if you can catch some of the head yourself and enjoy it while it lasts. The intensity will pass, even though the difference and specialness can remain. That's what it's all about. The only 'more' is melded into the big picture.