It’s not that Don is the victim it’s that she shows zero guilt or even simple acknowledgement that what she’s doing is wrong even if she ultimately doesn’t stop it.
Don and every woman he has an affair with does one or other. Everything she does is self-serving but acts likes she is the most caring, selfless person. That’s the self-righteousness.
She tells Don she knows the “special pain” of losing her father at Sally’s age yet she plans to take Sally’s father away from her…Ultimately it’s not that she truly cares about Sally’s pain but that she is trying to connect with Don
She sends her brother away not because she found him a great opportunity like she says (if she did she’d know or actually care that he hated it) but because he is a burden to her and she doesn’t want him around to interrupt her sleepovers with Don