I want a low key wedding

In fact I just want a marriage. I don't like attention, all eyes on me or the hassle of keeping people happy etc. I would gladly have a registry office wedding but my fiancé isn't keen on the idea. I don't care what other people think but I think deep down he does. He has loads and loads of mates which I think because they've all had big weddings he feels we need a fancy one too. He said he wants me to be happy, but I would be happy with something small and have a decent party afterwards and a decent honeymoon. I don't need pictures of me in a dress to look back on or fancy cakes and flowers. How do I convince him that this is all I want? (I know it's not just my day or what I want - we really can't afford a big wedding).