For evidence we have our 2 year rental contract, joint receipts for household purchases, facebook chats starting from May 2013, facebook posts, photos, comments also from May 2013 to present, receipts of money sent to me via paypal and western union (and we will be doing a joint bank account soon), we also have a jointly named group on facebook and jointly named Youtube account.
We also plan to get 2 or 3 letters of support.
A concern is that we both do not have friends or family here. We are not sociable type. All our photos are just us together at home and at places we visited Only my brother visited once for about a week and so we have some photos with him too.
We are very homebody type
You will be writing a letter to talk about your relationship. There you can talk about the progression of your relationship to where it is today. You can mention how you are homebodies but it will be strange to not have some pictures but not critical if the rest of your evidence is strong. Talk about the practical arrangements like banking, insurance etc. are you named in your partner health benefits or insurance? Those are the ordinary life moments that make a relationship real.