Ok I agree with pardes, let me explain why I think that Shiv should not be blamed, part of it is Ms Gauri's fault: ok here I go
1. Shiv was "FORCED" into this marriage.
2. He married Gauri with the intention
a) to prove his mom wrong, b) he wanted to get out of this marriage very quickly, thats why from day first he behaved with guari very harshly so that she would leave him. c) he wanted to break his marriage right from the begining.
3. He was very straight in letting Gauri know that he has no "love" feelings from him.
4. No matter what, he can never return her feelings, as he does not love her at all.
5. Even though he never disclosed his love affair with ipshita, he always said that the potrait is only girl he loves.
6. Shiv has a very charming personality, thats why Gauri fell in love with him.
7. Shiv likes Gauri as a person, and would consider her his "very" good friend, thats why he wanted her to go back to shahank, so that she can be happy.
All in all, its not Shiv fault that Gauri fell for Shiv, he tried his best to show his evil side to gauri so that she will leave him. Agreed that he didnt disclose everything to gauri, but why would he, it was not his intention to stay in this marriage for long, so thats why he didnt wanted her to find out unnecessary stuff. Over all shiv has a good heart, he cannot bear this guilt anymore and cant see gauri in pain.
I think his mom and girlfriend should be blamed for putting shiv in this situation, they are the one who told him to get married with gauri, be nice with her, wish her b-day, go to honeymoon with her, blah blah, plus initially mahen was real culprit, who forced shiv to marry her for the land, but since he left the show Ekta has to change the story, and now since shiv is leaving EKTA has to change the story again.
I think Gauri needs to wake up, the bottom line is that she love shiv way too much, her love is blind, she admitted that shiv gave her too much chances and signals, but she just does not want to accept it.