I don't see any big deal in keeping an opposite sex as a bestie even when both parties are in a relationship not marriage. Naturally, human being follows the magnetic law of attraction, the only issue we have in this situation is our society. Our society has define any slight relationship with opposite sex to be a severe one.
Until we change our orientation then we start seeing a lot of good in those things we normally neglect or disperse.
To have an opposite sex bestie only needs to be well define by those involved!
Hmmmm
Great insight
Thanks for contributing