FYI, this is a post to dump all of my Game of Throne/Cersei Lannister/Jaime Lannister/Twincest feels. Don't read it if you don't want to.
First of all, this pairing, the Jaime/Cersei canon, is perfect because of all of it's imperfections. There are people who judge it because they share the same DNA, because their blood is the same, they are made of the same flesh, because it is not just about them being related - it's about them being siblings. Beyond being siblings, they are twins.
I think people judge it because in our world, it is considered disgusting and wrong, in fact, people even go to jail for participating in incestual acts, but this show is not of this world. They are characters in a completely different world. Part of me ships them because in our world it is considered wrong when in theirs it isn't.
Cersei: Targareyans wed brothers and sisters for 300 years to keep the bloodline pure.
Jaime and I are more than brother and sister.
We shared a womb.
We came into this world together, we belong together.
Keep in mind, in ancient Egypt, royalty believed that siblings procreating kept the bloodlines pure. Today, we know that isn't true simply because it causes a very distinct genetic make up that causes disabilities. With Jaime and Cersei being twins their DNA is a carbon-copy of the other. (For more on how DNA works, check out
here.)
I get it though, this ship is wrong on so many levels because it is difficult to wrap our heads around. It is beyond the realms of our reality so something like incest is difficult to understand or support. But here's the thing: it still gives me a lot of feelings.
Cersei states in that same conversation that Jaime had the chance to be King. He is, after all, called the Kingslayer for a reason. But instead of sitting on that throne, he chose a different route. I think it's important to acknowledge the reasons stated but also important to consider that unstated reasons.
Jaime (and Cersei too) clearly knows it's wrong that they are sleeping together. He shows this on many different instances. In particularly on two different occasions; 1, when he pushed Bran out of the window, hoping he'd die so they wouldn't have to tell a soul and 2, when Cat approaches him asking why he did it. Sure, he stated outright to her that he had hoped the child would die, but when she asked him why he had hoped that he avoided. He knows that it is frowned upon, hell, she knows it too and that's why she tries to justify their actions to Ned Stark.
All the while, Cersei orders Ned Stark's death on behalf of her brother/lover because she is cut throat, no nonsense, and she has a lot of anger on Jaime's behalf. Jaime passed on his opportunity for the throne because of Ned Stark's action, but maybe his reasons were more complex. Maybe his reasons were because a queen would be desired and he didn't, couldn't imagine, any other woman as his queen other than Cersei.
Knowing that the only woman he could imagine being his queen never would be, maybe he stepped away.
In addition, it is stated that Jaime has never been with a woman other than Cersei. Cersei has also managed to avoid having intercourse with Robert since presumably the death of their son. Point being, there is a trust instilled in each other that they honestly don't have in anyone else.
Their father raised them with a mentality of "it is not what the Lannisters can do for you, but it is what you can do for the Lannisters." In this respect, they are encouraged to believe that Lannisters deserve the best, everything in the highest regard and with the highest honor. And what is better than mutual love between Lannisters?
Cersei says that "the more people you love, the weaker you are," and I think this demonstrates that she herself can't even believe some of the things she's done for Jaime. I honestly think everything she has done, she has done for Jaime. Selling herself out to Robert Baretheon for the throne isn't something I think she did for herself, I think she did it in hopes that one day Jaime would be king and she would be his queen.
Cersei even says that she doesn't feel complete without Jaime inside of her.
Their bond to one another is shared for a lifetime. Everything he feels, she feels too and vice versa. They shared a womb together, share DNA, share blood, share flesh - he was born in the world holding her foot, they have done everything in their life together and she can't imagine a world in which Jaime doesn't exist.
Without him, she is angry. She is taking down everyone against the kingdom, everyone who defies her or her son and when she is exhausted from that, she drinks. The only completion for her is missing and every time she looks at one of her children, she sees her brother, her lover, their father.
Usually, I am very adamant about the people in a pairing to be recognized as two completely different entities. I usually get very frustrated when they are not spoken about like they deserve individual attention. But, this pairing, they are an extension of each other and I just can't handle thinking of them any other way.
They just give me a lot of feelings and even though it is wrong in our world, it is a beautiful love story in theirs.