More like they deserve each other? They have been "partners" and being corrupted together. Diah is yes forced to be with Victor, but maybe she could have ran away from everything.
She did alrdy? She made them believe she was pregnant with Victor's child and that was how her engagement with the Grayans fell apart and subsequently was sent to another country by her father. Then she was given the chance to become the gallery's director so she came back since she is still the only heir as far as I know. Diah was probably holding onto the hope that since even Eiser managed to free himself from his family, she trusts she may be able to do the same with Victor. Nonethless, it is very visible that Diah was afraid and anxious of meeting Victor again when she returned but after a long while she now learns that she would never truly escape from his clutches which is also due to their long history of being in each other's life from a young age, so why bother trying so. Thus, her only available resolution was just to face it where sadly only drugs could ease her during such times. So honestly, in my opinion even if she runs away for a 2nd time now, Victor is definitely gonna chase her back.
I'm sorry but are people really shipping diah with victor? Seriously? He threatened to DRUG her to get information out of her! Y'all know what else he did? RAPE her! For fuck's sake please go reread ch 103 & 110. He loved her?? Y'all have goldfish memory I swear. He's a narcissistic, twisted pos and that's all he'll ever be. "Feel bad for him"? Don't me laugh. “but he was just broken inside