Honeymoon phase??

How long is the honeymoon phase? Some places say 6 months others say 1 year to even 2 years. How long does it really last. It felt like it was faded after 5 months I don’t know how but it did. Lol

Also do you know what causes it to end or triggers it to end ??I saw a video whatever person unknowingly thinks negative about the other person.