What is the worst thing that your significant other had ever lied to you about? how did you get through it?

Yes, I have had them lie to me. The worst thing was about cheating on me. Trust comes with actions. If someone is telling you one thing, but doing another, you can't trust them. If someone has a reason to lie to you and doesn't respect you enough to be honest even if it's about something you wouldn't like, the relationship is doomed in my opinion. Trust can't be given to someone, it has to be earned.