Please /u/SerKikoSmore, take their advice! I'll add the edit here in case you don't get to it. Sidenote, but happy cakeday /u/euklyd!
Now obviously Kaneki wanted a romantic relationship with Rize from the start but to me it became much more complex than that when he became a ghoul and especially when he was being tortured. The fact that Kaneki's mother abused sort made Rize's words even more meaningful when he was being tortured. "Even if it mean forsaking your aunt? Even if it meant hurting someone? Even if it meant taking her life?
Good boy. Thats right Kaneki Kun. There are times when you have to give up on one thing to preserve the other. Your mother couldn't do that. That isn't Kindness. Thats just being weak". " Can you still reamain on the side of being hurt?" .You all know the rest. Shes telling him that his mother was indeed wrong and that he should fight for himself and become strong. As I said before, these words gained more impact when we learned about Kaneki's abuse from his mother. All Kaneki has known is pain and the crazy thing about is that most of his pain has come from women. His mother, his aunt and of course Rize but Rize was diferent. Rize gave him the strength to become something more.
She gave him the confidence to surpass his limits and fight on. She is the one who came to his rescue inside his mind when he was being tortured. It wasnt his mom, his dad, Hide or even Touka no it was Rize. The thing is Kaneki doesnt even hate Rize. For all the things that has happen because of the night he walked her home he has still been eager to meet her one more time. As we see in the chapter 115 where Yomo has her locked a in a shipping container. Kaneki was aware that he was still alive because of Rize. Heres a quote of Kaneki speaking to the boy Yomo. " My body became like this because of Rize-san.(Notice he still refers to her as san? If im not mistaken this means he respects her.) But when I fought with the Investigators and when I was almost killed by Yamori.... what saved me at those times was Rize-San's Kagune. I... want to see her."
The boy Yomo told him that its not good for him to see her now and Kaneki got angry until he heard her and ran straight out the door with no hesitation to see her. Once he sees the state she is in he says these words. "Rize,, Its me Kaneki... ever since that time I've ahd to go through a lot. I became a ghoul.... worked at Anteiku...Many times I thought i was going to die.It was nothing but hard ship.(Then he said with a smile.) But even through all that... I couldn't bring myself to hate you. Weird huh? I wanted to talk to you."
One last quote from this " If the Rize i knew doesnt exist anymore... my strength was nothing but an Illusion I'm just a normal human just Kaneki Ken...If there is no Rize.." This is what IM trying to say. Rize in Kaneki's mind is the only mother figure that helped him live. Its a very strange relationship but very interesting and hard to put into words. Rize and Kaneki's relationship is my reason for why I keep reading Tokyo Ghoul. So yeah Basically, Rize is Kaneki's mama. His true mama in my opinion. Rize will return in the series and once that happens, depending on Kaneki's reaction may bring you all to agree with me. Im sorry I know this is a long post but one last thing I feel like I have to mention. I was put into a situation where I felt complete fear.Now we all have seen scenes in movies when grown men literally call out to their mom when they get afraid. We ussually laugh at it but I can assure that the concept is very much true. When i felt this surge of fear I found myself running out of my room and calling for my mother. Kaneki was in a situation where he felt nothing but complete fear when he was being tortured by Jason, and who did he call?