He may have trouble loving you per his definition of love. Do you know what that is? Specifically, how he's defining it?

He may be defining love as an impossible-to-achieve level of perfection and therefore not sure if it's even attainable or when, because it's so esoteric or abstract.

I would suggest defining what love means to you, and how that compares to liking someone, having an affinity for someone, what a friendship means, etc.

Until you both can define what love is, it's clear that there will be mismatching going on until you both understand each other.

Maybe love for him is only via the actions? Maybe love for him is something entirely? Remember, people love pets, love their family, love their job - but yet these are all different forms of love.

It would be worth it to sit down and have a discussion just on the word itself.