Question: You keep referring to Betty's "affairs of sorts". What exactly are you talking about? What are you trying to equate with Don's multiple prowlings? I think it would be interesting to flesh out the double standard here.
Look, I admit, I have zero problem with either of them "prowling". I think there is hypocrisy in believing that doesn't happen, but que sera. But as far as why I find Betsy's more problematic, it's because Betsy goes for the complete contradition.
Don has his affairs, keeps them quiet, whatever. It happens. It doesn't make him a great person, but it is what it is. Betsy spends the entire first season courting a horse owner who's engaged because he's from "old tradition" and makes out with him in the barn and yes, realizes she can't take the next step. Then she bangs a guy in a bar.
Honestly, no real problem with either situation. But to immediately follow it up with the duplicitous lie of "I'd never do that to you.." hah. Don didn't ever chose to take the moral high ground on the sex issue "If it happened to me, I'd tell.." This season has been full of Betsy looking for ways out, which is fine. In "Souvenir" (8th episode) she basically regales Sally as to how she longs for that "first kiss" experience. She then tells Don she wants to live in a better town, have better friends, move up the social ladder. In previous episodes, we saw Betsy go to a parent teacher conference and basically walk out, refusing to deal with her daughter's new troubled behaviour despite the fact that Carla, the maid, has warned her for two seasons now.
As far as absentee father.. I think we're judging from snippets. Don was the only one who realized that his daughter was struggling and in trouble, not Betsy. Betsy's general answer has been to yell and scream back or just walk out of the conversation.. or do something truly creepy (dolls from your infant who's named after a grandfather you're already terrified of?)
Her storyline is about to get interesting. But just like season 1, where she used Sally as a prop to get her close to a horserider, she's using the kids only as an afterthought to move on to what she sees as a Bigger, Better Deal.. her judgement is clearly laid out; she knows absolutely nothing about Mr. Francis. But she knows enough that he's a BBD, at least in her mind. And kids are just collateral damage.