I don't believe it for a second when Bo claims that John Derek was really "hurt" too by the divorce. (Unless it's how he looked to their friends). Even if she's sincere when she says it.
Break-ups happen, and one shouldn't objectify or dehumanize the other just because the relationship has ended (and Linda hasn't) unless it's warranted. But the thing Derek "loved" so much about Bo was her youth -- not just her perkier bosom, but her controllability (later, once she became more independent and assertive, he was okay with it, because he was crumbling and didn't mind the support).
But Linda was in the unfortunate position of genuinely loving the man. And for a guy like John Derek, so aloof -- focused and charming when needed but aloof and diffident -- someone who genuinely loves you is a pain in the ass. Or arse. Because true reciprocity, or the potential or expectation of it, seems like a threat to that "control".
Hence, the partner must be marginalized, devalued in certain ways, and absolutely cast aside.
Not everybody wants to be loved. The implicit intimacy becomes repugnant, or at least tiresome and romantically boring. It feels like a threat to his sense of cold autonomy.
As they say, familiarity breeds contempt. And all John had to offer was familiarity -- attentive and not-disinterested, but mere familiarity.
I'm sure he never really thought about Linda after she was gone. Even if all his wives were friendly with one another.
Basically, Linda was too good for him -- and she didn't want to know it. But he did know it.
Poignantly sad, because John and Linda always look more like "a couple" than he does with any of his other wives... And that's not just Linda -- it's the two of them together.
Ah, the human condition.