Untrustworthy Couples

There was one instance a while ago where I asked someone to keep something between this person and me and the response caught me surprise as a long time single person: "Don't ever ask me to keep something from (my significant other)". It's probably been over a year since that conversation occurred and I've grown as a person since then, but I still ponder about that issue.

Are couples naturally untrustworthy? Do you have to treat couples as an single entity such that if you tell one expect the other to find out eventually? Is there an unspoken agreement that couples will share everything with each other?

Maybe my friend's response was wise as it wouldn't put that person in a tough situation in keeping the trust of the friend that confided in them and maintaining the relationship with the significant other.

An interesting aspect is how much information of previous relationships should be divulged to the current significant other. I would think that most of the previous relationship information would be strictly confidential but it could possibly cause some tension.

After much thought and having many conversations, this is completely a personal preference. But it seemed that majority of the time, people said to expect couples to share everything with each other. It is probably better to stay on the safe side and assume that too.

Benjamin Franklin once said, "Three can keep a secret, if two of them are dead."

Note: Immediately after writing this, I realized that this aspect of relationships was depicted in Seinfeld by George and Susan in the infamous Sponge episode with the 31 inch waist and AIDS Walk list.