Communication should go both ways. IMHO anyone who refuses to allow another to express their opinions on the basis that it will upset them doesn't really care about anyone but themselves and is not really worth bothering with. Maybe they would be less 'upset' if you just ended that relationship. Maybe you could turn it round and tell that person that NOT talking about the subject is hurting you. If they don't get it then........

As Dorothy says, life's too short to have to keep considering other people's feelings at the expense of your own.