1stly remember that this is ekta, i dont even think she thought aman was going to turn out psychotic! in the beginining i think he was going to be the good guy the opposite of rahul.
i mean to be frank rahul has been a b*****d in his treatment of kk, we all blame naina but love or no love he WENT ALONG with it all and then instead of admitting it continued with the deception of kk in the wrong.
anyway back to aman the best thing to do is split him into 2- pre killing of naina and post:
pre-killing- was kk best friend, believer in love, loved kk but knew it wasnt returned etc
post-killing-a power hungry control freak murderer!
i agree with mita_m that aman pleasure is in being able to control kk. he likes the idea of being the puppetmaster and everyone is dancing to his tune-thats y he didnt compromise himself as a lawyer cause he wanted/needs the praise acceptance of his family.
with kk he knew she was never going to love him thats y while rahul was in jail he set things up for kk to hate rahul, however once the truth was known his plan changed.
before getting that the questions comes to WHY did he tell kk the truth? he said himself he couldve said the items were returned to him from the court or any no. of excuses but he told the truth, reasons:
1. makes for a more interesting story!
2. from aman side he knew rahul was out, he knew he was innocent, matter of time before a-kk realised that too (he didnt know that nainao had already told her) or b-that kk love for rahul would overcome everything she did after all forgive him for tearing down her house and making homeless her family!
so by telling her he retains power over her especially by threatening rahul he makes sure she tows the line! this is the only way he can have her then so be it especially if it means rahul cant have her!
his love is in fact hate; he hates the fact kk loves rahul even after all hes done to her, he hates the fact that after caring and helping her she doesnt love him, he hates the fact he knows wht he has done and is doing is wrong but even knowing all this he hates the fact he has lost.
remember rahul said to nainao that if uve never lost a case aman has always won his cases- before we all assumed swarti killed herself but later found out that aman killed her cause she was leaving him (forget the pre-naina swarti-aman love) basically he was LOSING her and he couldnt take it so he killed her-in his eyes he WON.
with kk couldnt do another murder (also kdmh would end! cant have that) but he wins not her love but everything else and her suffering is his win for her not loving him and if rahul suffers too then icing on the cake. but hes not bothered abt rahul just abt making kk suffer, u could see his anger whn kk got up forgetting her ankle and worried abt rahul and he said wht husband would take his wife to her lover-with venom!
as for the physical side even he knows that kk will fight him on that especially in the house and he def doesnt want that that y he wants the honeymoon.
well this is my take on aman i liked him whn he was good and wanted him and kk to get together-thought it would far more interesting in them bring down rahul and naina and in parts u could see ekta playing with that possibility too.
being evil did take abit of getting used too but u needed somebody to be the baddie and with naina dead not much of a choice left! and hes grown in the role. so back to the wait and see.......