I think the deception by Adalind at the end of season 3 was Juliette's breaking point although it took a whole season to play out. She knows logically that Nick was duped into sleeping with Adalind but emotionally could never get over it.
I think the main reason is the way Nick acted afterwards. Juliette sees the lingerie on the floor and gets immediately suspicious. She observes his behavior and sees how giddy Nick is. Lets be honest, Nick was pretty much in euphoria after having sex with Adalind. We know he immediately wanted to go for seconds. Nick then made a statement that Juliette could never forget. She asks Nick for an explanation and he says "we made love". Juliette is probably thinking he could have sex with anyone but only they make love. The fact that it was with Adalind was the worst possible scenario.
Juliette agrees to become Adalind and have sex with Nick. She asks him how was it? Nick pleads the fifth and says either response would land him in trouble. I get the impression Juliette knows he enjoyed it and was fine with it until she looked in the mirror. She hates this woman with all her heart and now her long time boyfriend just had a passionate session with her form. Juliette pretty much gave Nick the entire view of Adalind's naked body and knows Nick is enjoying it. She has to be thinking what is it about Adalind he likes so much although it doesn't take a genius to figure out. Juliette also hears from Adalind that it was a "real whopper" that she now knows is true.
Juliette then undergoes her transformation into a Hexenbiest and eventually learns to relish the power. She now understands why Nick didn't want to give up his power. She then plans to use this power to kill Adalind. Juliette, Nick and co. have been victims of Adalind. Juliette told Adalind in season 3 that if Nick wanted her dead he would have killed her the last time she showed up. Now that she has all this power and Adalind has caused even more damage since her last visit she's probably wondering why Nick hasn't killed Adalind himself. He has threatened to from time to time but never went through with it. Juliette knows he's killed other Wesen so why not Adalind?
After this, Juliette finds out Adalind is pregnant with Nick's child. Nick is protecting his child but Juliette sees it as Nick choosing Adalind over her. Juliette makes a joke about them being a cute couple and Nick says you know how this happened. Juliette responds with "I sure do. Adalind told me it was a real whopper". The interesting thing I noticed is that Juliette has a straight face and looks directly at Nick and ignores Adalind while saying it. It seems like she's really upset with Nick at this moment even though he was duped by Adalind. It comes off as accusatory of Nick.
I remember at the end of season 1 when Nick tried to get Juliette to get help for the cat scratch. During this conversation, she says Adalind is an attractive successful woman whose life Nick saved. She couldn't figure what Nick had against Adalind now. She asked him point blank if he had some type of a relationship with her. This was all forgotten when Juliette learned the truth but seemed to come back with a vengeance last season. It seemed like all her worst fears were confirmed and knows Nick at the very least would never want any harm to come to his son's mother. Combined with feeling rejected by Nick, I understand why she went off the deep end.
This could have been a better storyline had Juliette's descent not been so rushed. It only took a few episodes from her putting aside her own issues to help rescue Monroe to full-blown psychopath who tries to murder her loved ones. They also shouldn't have made her so powerful because it makes me think the other characters are wasting their time when Eve can defeat more enemies than the rest of them combined. I think Juliette described it best while in her jail cell. She tells Nick "you used to be the special one" which we now know is the definitive truth.
I think the main reason is the way Nick acted afterwards. Juliette sees the lingerie on the floor and gets immediately suspicious. She observes his behavior and sees how giddy Nick is. Lets be honest, Nick was pretty much in euphoria after having sex with Adalind. We know he immediately wanted to go for seconds. Nick then made a statement that Juliette could never forget. She asks Nick for an explanation and he says "we made love". Juliette is probably thinking he could have sex with anyone but only they make love. The fact that it was with Adalind was the worst possible scenario.
Juliette agrees to become Adalind and have sex with Nick. She asks him how was it? Nick pleads the fifth and says either response would land him in trouble. I get the impression Juliette knows he enjoyed it and was fine with it until she looked in the mirror. She hates this woman with all her heart and now her long time boyfriend just had a passionate session with her form. Juliette pretty much gave Nick the entire view of Adalind's naked body and knows Nick is enjoying it. She has to be thinking what is it about Adalind he likes so much although it doesn't take a genius to figure out. Juliette also hears from Adalind that it was a "real whopper" that she now knows is true.
Juliette then undergoes her transformation into a Hexenbiest and eventually learns to relish the power. She now understands why Nick didn't want to give up his power. She then plans to use this power to kill Adalind. Juliette, Nick and co. have been victims of Adalind. Juliette told Adalind in season 3 that if Nick wanted her dead he would have killed her the last time she showed up. Now that she has all this power and Adalind has caused even more damage since her last visit she's probably wondering why Nick hasn't killed Adalind himself. He has threatened to from time to time but never went through with it. Juliette knows he's killed other Wesen so why not Adalind?
After this, Juliette finds out Adalind is pregnant with Nick's child. Nick is protecting his child but Juliette sees it as Nick choosing Adalind over her. Juliette makes a joke about them being a cute couple and Nick says you know how this happened. Juliette responds with "I sure do. Adalind told me it was a real whopper". The interesting thing I noticed is that Juliette has a straight face and looks directly at Nick and ignores Adalind while saying it. It seems like she's really upset with Nick at this moment even though he was duped by Adalind. It comes off as accusatory of Nick.
I remember at the end of season 1 when Nick tried to get Juliette to get help for the cat scratch. During this conversation, she says Adalind is an attractive successful woman whose life Nick saved. She couldn't figure what Nick had against Adalind now. She asked him point blank if he had some type of a relationship with her. This was all forgotten when Juliette learned the truth but seemed to come back with a vengeance last season. It seemed like all her worst fears were confirmed and knows Nick at the very least would never want any harm to come to his son's mother. Combined with feeling rejected by Nick, I understand why she went off the deep end.
This could have been a better storyline had Juliette's descent not been so rushed. It only took a few episodes from her putting aside her own issues to help rescue Monroe to full-blown psychopath who tries to murder her loved ones. They also shouldn't have made her so powerful because it makes me think the other characters are wasting their time when Eve can defeat more enemies than the rest of them combined. I think Juliette described it best while in her jail cell. She tells Nick "you used to be the special one" which we now know is the definitive truth.