。
I'd like you to have a look at my stamp collection.
Literal
I [of-の] stamp-collection [object-を] see-get-want [but-のだが].
見てもらう literally 'receive the [favor of] seeing' — i.e. 'have [someone] look at.' The ~たい adds desire, giving 'want to have [you] look.' The ~のだが ending softens with explanation + conjunctive が ('but'), leaving the sentence trailing as a polite indirect request. Typical conversational opening for requesting a favor.