wow - whatisis - a slap of truth.
I thought about this trying being friend with my W - and yes, at least for me, was a desperate attempt to not let her go - the last thing I could hold on to... "maybe.... we can still be friends....", while her "we can still be friends..." was more of an attempt to sweeten the fact she was leaving.
But ironically so, I think a betray form a best friend is much less forgivable then from a spouse.
I still think H4H did the right thing because they ended up having a good day together, if it was going to end up with fight and R talks than would have been different.