She wanted him to change in order to suit her own needs under the guise that Matt (Daredevil) doesn't really make a difference and isn't needed anymore.

In The Defenders, I was under the impression that Karen was terrified of him getting exposed. She was 100% correct when she told him that he was finally just getting his life back. When he revealed his secret, he had nothing left from his regular life: he had lost Karen, he had lost Foggy, he had lost Nelson & Murdock. Since then, he’s started practicing law again (and kicking ass at it), he and Foggy are on much better terms even if they’re not 100%, and Karen is at the very least ready to be friends again while they continue to “figure themselves out”. Both Karen and Foggy recognized that Matt’s two lives were VERY close to colliding in The Defenders (and they’re not wrong; it really shouldn’t be that hard to figure out who Daredevil is at this point if the right people are paying attention). Karen doesn't want Matt to stop being Daredevil; she doesn't want to see him lose everything that he’s finally just getting back for a second time.

That’s why I’m so sick of the “Karen doesn’t support Matt as Daredevil” claims; go back and pay attention. Karen is not anti-Daredevil, she has always recognized his value even before she knew who he was. When Matt tells Karen when picking her up at the Bulletin that it’s something he has to do her response is “I know.” Of course, Karen was also getting mixed-messages from Matt, hearing from him a few days earlier was that he was done with that life, so I think it’s pretty understandable why she was so confused he was taking it up again. She’s not anti-Daredevil; she’s anti-Matt lying to her.