Womanizing means bedding every other woman ? I dont think so.
As Rajnath made it clear in the flashback,' Aiso chizo ko main ghar se dur rakhta hun'. That will explain why Suchitra was spared.
Sakshi never loved Rahmat as per Akram's words. He was like a step towards success. We know Sakshi was a nobody. SHe had very little in life and Rahmat's name and house gave her basic identity. Rahmat on the other hand found a very good mother, friend and wife in that woman. So all was well until Rajnath didn't appear in the story
Sakshi showed great interest in Rajnath's lifestyle. Quite common thing to have for a young girl, as we might all have for Ranbir Kapoor or Salman Khan. Also that she was a girl from streets she had profound liking for a man from the royal palace.Rajnath noticed her likeness for him and started to exploit it making it a good extra marital affair. Sakshi did love Rajnath at one point of time as much as Raima did but unlike Raima she doesn't accept defeats. Be it a dog or the manager in the orphanage, she will take what is rightfully her or at least she believes so. So, if Rajnath won't marry her she has his ways to do it.
Rest is yet to be known. Did they both kill Rahmat ? Did Goenka advice her to kill him ? Rahmat was a media person. May be Raj used Sakshi to keep him away or completely wipe him out?
BUt Sakshi loves Rajnath for sure. She was disheartened to know Raj was cheating on her. Unlike Rahmat and Raima she didn't kill Rajnath. Killing him would not have mattered much to her if it was only about money because she still would have been Mrs. Goenka.