Should we break up? Why he doesn't want to introduce me to his parents? Why he doesn't want me?

Hi everyone! We have been together for year and a half, but there are some things that concern me. Our relationship is great, we have a lot in common (even priorities and goals), we enjoy spending time together,we never argue, everytime we apart we spend hours talking on the phone, but he doesn't want to take any further steps. He struggles calling me his girlfriend (explaining that with his aversion to word 'girlfriend'), he doesn't tell me that he loves me, he doesn't mention me in his plans for the future, he doesn't want to introduce me to his parents or even tell about us his brother, despite that we met and some times we spend time together (me, boyfriend and his brother). We had many conversations about this, but he never explained to me his behaviour, telling me I'm whining and looking for comparison. Is there anyone who can help me understand this man and my relationship with him?