Most girls have experienced this at some point in their lives. You get a boyfriend, and you're so happy together, and then the home wrecker comes into the picture. The home wrecker can be an ex-girlfriend, a girl you don't even know, or even a "snake in the grass," such as a friend or family member. They start with something simple such as a text, message on Facebook or Instagram, likes on photos, or Snapchats. Then they weasel their way into the relationship as much as possible. They will try to cause problems, and even break up the relationship, usually for their personal revenge or benefit.
So, home wreckers, this is for you. First off, you are ruining your reputation. Girls talk, and I can promise you that if you break up one relationship, every girl will find out and run from you like you have the plague. No one wants that untrustworthy drama in their lives, except maybe you.
Secondly, karma is a b****. You go around messaging guys with girlfriends, thinking nothing of how it will ruin their relationship and never considering that the same thing could happen to you one day. That would really suck if you finally grow up and get a boyfriend and then you meet, you. Lastly, what you're doing is very disrespectful, mainly to the girlfriend. You cause trust issues, arguments, all which is unnecessary. I don't care if you're asking for some old clothes back, casually sending them a Snapchat that you posted on your story, or whatever your excuse is, it's wrong. You are disrespecting a girl you probably don't even know and messing with a guy that she cares about greatly. You may think that messaging your ex or your "best friend" is justified, but if he has a girlfriend, it is just off limits. Put yourself in their shoes: would you want some random girl, especially an ex, messaging your boyfriend? No, probably not. So just don't do it.
Thankfully, some of us have boyfriends who don't let these home wreckers ruin our relationships. However, the disrespect is still there, even if the relationship is strong enough to withstand your drama.
So home wreckers, save yourself the wrath of a crazy girlfriend, and the ruination of your reputation with all girls, and just leave the guys with girlfriends alone.