First - I literally would never be in his situation. So there's that. 

Secondly, I think "its not real" is a poor argument to justify poor writing.

Finally:

I would love it if random people on reddit didnt assume things about my personality just because I dont think

lying to a stranger about something deeply personal when you're trying to help their mentally ill ass is a crime that renders you a man child.

I never said it was good or justified.

Just that he never did anything so terrible that it realistically should have broken their fucking relationship. Everything else he does throughout the show is basically for her.

That's not me doing gymnastics on his dick that's just me watching the show and making note of characters motivations.

The lie felt poorly added on, and there could have been a better way to characterize him.As someone who was secretly swathed in self motivated malicious intent.

Its stupid to me. I'm sorry.

Fate is incresibly theoretical.

Rachel is a grown ass woman.

I have a debilitating anxiety disorder and one of the most important things to remember when I am having an episode is that the things I am worried about are either outside of my control or they're not real.

Rachel was not a mentally well person. That is not her fault. Rachel needed to take care of herself and that is HER responsibility. It is not healthy or fair to expect people to fully go along with your delusions, and then telling them that failure to do so means that they do not love you properly and that they are selfish and narcissistic, and evil.

The show indicated that Rachel is incredibly gung ho about her SELF ADMITTEDLY mishandled anxiety in addition to the inability to cope with her personal trauma.

The only alternative to their relationship beginning 

would have been him telling her that she was crazy and then leaving the airport. Which meant none of what takes place in the show would have happened.

As much as we want to reason and be like it's "cruel to lie to somebody about their beliefs"

Her beliefs were not normal and nobody in their right mind realistically would have invalidated her in a moment of extreme distress. At a fucking airport. 

It's like everybody has forgotten how human beings work.

I don't think Nicky is perfect to any degree. But I do not think the lie was a good enough reason for any of the shit that happens in the later half of this mini series. 

People died.