What is your relationship like?

So my boyfriend and I are both 16. We have been together for 3 years, on and off. I've noticed that we're different to a lot of couples we've come across. We're not affectionate with each other. We don't hold hands in public, we don't kiss in public, we're not even shoulder touching when we're walking. We don't have nicknames for each other or 'boo', or 'babe'. We still say 'I love you's' when we're saying goodnight. We find it uncomfortable or cringy showing 'affection' to each other. I don't know why :/  We kind of just act like best friends. But we still laugh at stupid things and we have pretty long flowing conversations and enjoy spending time with each other.  It's just awkward when other couples walk past holding hands, it makes me a bit sad but I get over it. When we're alone, we get 'affectionate' but only to the point where its lustful.  Is anyone else's relationship like this? Is my relationship based on lust? What should I do?