prior to the fear hole episode, Diane was characterized as an ordinary woman - an ordinariness often compared to Jerry per word of god + apparently in Beth's perspective:

And if Morty needs to risk his life traipsing across the galaxy with her insane alcoholic father, it's better than Morty growing up in safety and ending up like her mother or her husband Jerry who she considers to be unremarkable and unredemptive and therefore undeserving of her affections (x)

[Beth] has been defining her life by her marriage straight out of high school to this unremarkable man that she in her mind compares to her mother, while fetishizing exceptionality in the form of her father. (x)

 Sometimes they don't even admit it to themselves but they say, “My dad's so fucking cool, he got the fuck out of here. And my mom's such a bitch she's always asking me to clean my room. That's why dad left. She probably asked him to clean his room.” And [Beth] fetishizes exceptionality. She believes that Rick, as crazy as he is, is the better of her two parents even though she was raised by her mother and she blames her mother's unremarkability on her father”s departure and will do anything to keep her father back in her life. (x)

Rick himself alludes in S1 that he and his wife were "stranded in a dying marriage". but, when she makes her appearance six seasons later, she's a former employee at NASA who had her master's thesis on nonhuman intelligence. according to Heather Anne Campbell, Diane found "the nihilistic dark stuff that Rick's doing is funny". Heather stated that she wanted Diane to be the kind of woman that he'd love, a match. she did say that they were exploring Diane "through the lens of fear", so maybe she wasn't guaranteeing that this was truly who Diane was, but i hope it wasn't. the original dynamic prior to this episode was profoundly more interesting and all the more tragic.