I think he's either cheap or commitment phobic - maybe both. Even a small gift - when you're out & see some small item - just something that says I notice what you like & want to make you happy.

A man does not have to buy you gifts, but it would be nice on your Birthday and Special Occasions. If you are not even getting dinner or flowers just treat him as te friend he is and nothing more. Every women likes to be pampered. Have a discussion he may have been burnt in the past and is being cautious.

I'd say he was just cheap, does he take you to dinner or buy you flowers?

Eighteen months and no gifts? I guess he is not into generosity? It must not be his language of love. I would just be flat out honest! I would ask him why he is chosing not to give gifts.