We humans have a problem. We make judgement faster and we expect everyone to accept our view. And that is what that has happened to Kaikeyi. Her whole idea of being an ideal wife was because of the fact that her father sacrificed her mother as her mother was selfish. So an inborn fear was there in her that her husband can sacrifice her and all her steps she took was because of this fear.
And because of that we can say Kaikeyi was never her true self. If you look unlike other queens Kaikeyi has more warrior like qualities. You can really call her a tomboyish woman of those days. One who had a free will and independent thoughts.
But growing up in an environment conditioned to believe anything not feminine is selfishness as part of the woman her true self was buried under the garb of ideal wife.
And this ideal wife expected unconditional love and loyalty. When she didn't get it, her true self started coming out but in a negative way.
We have to know two things here. First never make any judgement without knowing the complete story. Especially stories about past. It always has 2 sides. And if we decide to live life on half baked truths or rather half knowledge then results can always be disastrous.
You cannot become ideal wife, ideal son or ideal whatever because of fear or some pre conceived notions controlling your actions.
Second there is no point burying your true self. You are doing the biggest disservice to yourself and a society at large when you bury your true self and pretend to be someone else. Because you cannot keep that persona for long. Your inner world will always be at conflict and one fine day everything will spill out and most probably by that time your worst fears also will come true.