Riddhima character was very cheap i must say, who shows their body to someone who their supposedly don't love?. Although Riddhima started out as a "innocent " character she definatly changed over the course of 2 years to become a woman with no self respect what so ever.
I dont believe that Riddhima ever loved Armaan or Sid, i think she just loved herself too much .
The attention of 2 good looking went to her head.
I can understand why she became crazy, she must have been the 'ugly' girl at school then when she entered sanjeevni she started getting the attention she so desperately wanted. I think having one guy was already over whelming but having 2 men go after her obviously tipped her over the edge.