My thoughts on the fiance are that she is NOT really in denial, nor is she really standing by him- I do NOT believe she thinks he is innocent until proven guilty, I think she KNOWS he is guilty- but what is she supposed to do? She has to tread carefully here...this has ruined her life.
It is probably hard to turn all your feelings for someone off just like that, if she truly never saw any signs of this side of him. If Casey Anthony admitted to killing Caylee and said she just didn't want her anymore- I don't think the Anthonys would support her at all but I think if they had any love for her in the past it would be hard for them to just forget about her and not love her anymore.
I think that's what going on here. The fiance has been through a major shock and trauma- she was a bride planning her wedding in just a couple months- suddenly ALL of that life is gone. She has to not only cope with this but to get past it and start all over. I am sure it has not hit this girl yet--she has not processed this- her fiance KILLED someone. Someone just like herself, a young woman with hopes and dreams and a family, who was trying to make her way through life. (The fiance needs to consider this- no matter what the victim was doing and no matter their background they ARE similar, neither one of them deserved to be victimized by this man).
I am sure the fiance realizes PM has done some unforgivable things. Who knows, she might still be in shock or she might be angry, but maybe she just wants for justice to be carried out. And maybe she is just trying to act like she is supportive of him so he won't try to kill himself, although I am not sure at this point that he cares what SHE thinks of him!
I just don't buy that the fiance is really supporting him. I just think it was a statement made to get the press off of her, it was a very lukewarm statement. She wants to grieve privately, doesn't want tv shows chasing her for interviews either way.