I hope you stay and post... but go at your own pace you are comfortable with???
I think "love" changes with time... after the glow of "first married" then a real, livable relationship (should) builds... growing and loving together. If that doesn't happen, when the honeymoon is "over" ...there's nothing to keep them together.
Yes, best friends is highly subjective. But what's good...we each get to define it for our own self! I agree with what I think you're saying... once "friend" always friend, no matter what. The friendship changes as we do...but it's always there

don't hate you at all... good to see your post... do your best