Some people feel that couples shouldn't keep secrets from each other in a relationship, but can too much information be destructive?
If you were to ask someone what is the most important thing in any relationship, the majority would always say communication. Couples have to maintain an open and an open heart to keep the peace. Others might not agree so much. Everyone has secrets and everyone has their own right to privacy but in long-term relationships it is expected that couples know each other thoroughly. Sometimes not telling your partner all of your secrets kind of keeps the mystery suspenseful because it's like "Wow what else don't I know!" At the same time there is a slight difference between privacy and secrecy.
When there is privacy, it's usually deals with personal space. It could be certain websites that you have that are under your name or password, or certain items that you use you don't want your partner to snoop through, or a particular remedy or activity that you do during your me times. Secrecy has to do with things that you are hiding that you could be ashamed of unsure of. Some examples would be promiscuous past, criminal record, not being able to reveal your real orientation, etc. Secrets usually come out at some point and it can make or break a relation and privacy has to be a respect factor between you and your partner.
Having secrets and being private can be critical in a relationship. I agree that couples don't necessarily have to know every single thing about their partner especially if the partner is uncomfortable talking about it. Mystery can be exciting but it also depends on what it is. Certain secrets have to be in order for the partner to be aware but again it starts with stable communication. In order for couples to move forward they have to compromise.