Olivia's relationship with Cassidy is going to end very badly when she admits that she's still in love with Stabler.
It's that kind of crap that has marred SVU. Especially in last week's episode when she came down hard on the female cop for expecting her male partner to love her back. Why couldn't there be a friendship and a working relationship? They seem to be able to do it well with Fin and Rollins.
I don't think Benson was in "love" with Stabler. They had great chemistry together, yes, but only on the force. She may have had a crush on him but she was also friends with Stabler's wife so there's no way Benson would have been a homewrecker.
Benson and Cassidy really is a good idea, though. I do believe that the only way she can find love is with another cop. And Cassidy is different enough from her to make it work.