First of all,relax and be glad that you are living a completely normal life. This happens with all. We crave for the things that we miss in our lives,thats human nature. I think you take your relationship like a burden,just an assumption based on the fact that you search for isolation and peace when you are in a relationship. Maybe you should take it a bit lightly,give your partner their space and have some for yourself too. Enjoy it rather carrying it as a burden. I would recommend you make more friends and eventually you will find some people with whom you speak your heart out without the burden of a relationship. Just relax because this is what growing up is. This is faced by one and all. Best of luck.