How can you stop someone from becoming a "yandere"?

[HorsesandMOARGaloar 300]

"Yandere" is a Japanese adjective that refers to "a person who is deeply obsessed/in love with someone, that he/she may resort to even killing off potential competitors to him/her or threats to his/her loved one".

 

How can you prevent a person from becoming into this kind of vicious personality?

[StarBot 85]

Make your friends enjoy other things and try new stuff.

[HorsesandMOARGaloar 300]

Bonus points if you are raising a child, especially if he/she is adopted.

[Minepro 107]

I'd say try and get that person to not be very clingy for long. Extinguishing flames before the source of a fire starts up is usually a sure fire way to keep anything bad from happening. That's just my POV on it. I've done that with my mother and it's very hard to get somebody off once they start.