You say you guys do things together often, talk a lot, he goes out of his way to help you and he wants to go on holiday with you... yet, you're worried about "compliments"? Perhaps it's due to the large differences of how I see view a relationship- as compared to your views on it- but, I still don't understand why you need him to say "nice things" when he's putting his words into actions.
If he says "I can't believe you'd date me..."- to me, I'd just see it as 'okay, and...?' but, if he were showing it (doing things with me, being around me, talking to me, going out of his way to help me and proposing to go on holiday with me, etc.)- then yeah, I'd understand why he'd say that comment in the first place because no one in their right mind would want to be around someone (or help them with anything) if they didn't like them.
I wouldn't view it as him not being interested in you. Judging by what you've said- he seems like he's showing you that he likes you. If you were to flip this scenario: he talks about liking you but, never shows it vs. he shows that he likes you but, doesn't verbally tell you as often as he once did- which would you choose? (I think he might have said those things because the relationship was so new and there was no history between you two/to go on but, now that you guys are together- he's able to put those comments into action.)
Again, perhaps it's my views that I find superficial comments as a mere "side dish"- rather than being the "main course"- that I just don't find it to be that bad of an issue. If it's comments that you want; I would express it to him and maybe he'll put in the effort to say things but, I highly doubt it will mean anything to him if he doesn't feel compelled to say such things on his own.
Anyways, best of luck.