Why do people we have become very close to and love tell us "I'll never leave you" and then they end up leaving us?

[sage2021]

Are they just lying to us? Is it so we won't leave them if they tell us that?
Why bother saying that to someone if you know you aren't the type of person to stay?
What makes them leave?

[dustybiker2]

People evolve and change. We are not stagnant. We are formed by our daily challenges. If communication is poor, interest is dwindling or maybe the relationship wasn't that great to begin with things end. You have to nurture relationships, put in the effort or it just becomes two people living together.

[sage2021]

@dustybiker2
I wasn't asking for me personally l, I saw some one talking about this on another post so I thought it would be a good question.
Thank you

[exitseven]

damn, it is tough. I knew people that I thought would be part of my life forever and I have not seen them in 20 years.

[FunkyMonkee]

They were probably talking out of their ass!