I agree with Willow. I have a niece and nephew who I have only met a handful of times. I love them because they are my sister's kids but I have no attachment to them. They barely know me and I barely know them. Similarly with my siblings and my kids, they care about them but they are really just kids they barely know.

It gets better with age, now DS1 is 5 he can chat on the phone with my sister and brother so they have more contact and hence there is more of a bond. This is just one of the side effects of living far away from someone I guess, although it is hard when you realise that there is no real relationship with little people who are so closely related to you.