Sex can be a small thing if both people don’t want sex.
However your relationship without it, is basically friendship, companionship, and emotional love.
And that’s perfectly fine if that’s what you want. The issue becomes when you don’t want a relationship that’s effectively a friendship. Which this is. You’re basically best friends. Partners, but not physically.
Speaking to him about it is difficult, for the simple reason that you don’t want him to feel forced to have sex with you. To feel he has to or loose the relationship/friendship. That will never work long term. He’s not going to spend his life having sex with you when he does not wish to, and I assume you’d not want that either.
The basic issue here is he doesn’t want to. If he did, he’d have sex with you.
Not wishing kids takes the pressure off him to ever have to have sex with you repeatedly in a given period when he would rather not.
As said, I’m not sure speaking to him is the answer. It’s not going to make him suddenly want to jump you.
I fundamentally agree with you, it’s a small thing in a relationship that is simply a loving companionship. It’s a very big thing if it’s a romantic and physical relationship.
You need to decide if you’re ok with what will eventually be a sexless relationship. One with love, affection, maybe even cuddles, hand holding etc, but no sex.