If you confide your most personal secret to your bestfriend, should they keep it even from their own spouse? This secret effects everyone, including the spouses.
If you told someone something in confide confidence (unless it's a crime like murder or rape), your friend should keep it to themselves
Yes, but if it's something that important that I don't want anyone else knowing, then I wouldn't tell my best friend.
I don't expect loyalty from anyone but only to myself!
depending on how crazy the implications of this secret, if it affects everyone in both couples I wouldnt tell my best friend unless I was positive they had sufficient intrinsic motive to keep the secret for themselves. Or unless I wanted it to get out for sure but not be responsible for it directly lol.