I mean... how often does this conversation come up? Is he constantly asking you to put him against Leonardo or Channing? It is a forgone conclusion that most of us aren't as hot as (insert attractive male celebrity). If we were, guess what, we wouldn't be managing that Denny's or working mid-level finance jobs. We'd be male celebrities. The fact that your man thinks you are the queens t*tties when it comes to looks is fantastic. But you don't need to (nor should he expect) a knee jerk confirmation that he is too. He is obviously attractive enough that you date him and sleep with him. Where is it written that he should out look David Beckham?
Lastly, if all else fails, use some Disney magic on him. Tell him, sweety, everyone has a unique look. No two men or women are created equally. That's the beauty of life. His sexiness is reserved for him. Just as say Paul Walker, Bradley Cooper, Ryan Reynolds and Jerry Seinfeld's are only theres.