Why do some people double date in their relationship?

[Ja Sa Bong]

Double dating is sad to have from any one you're in a relationship with because it means that you were never enough for him or her and the person doesn't have the dignity to tell you and end the relationship but only stay in there to be using you for their selfish gains.
If I find out you're double dating in a relationship with, it's over immediately.

 

[Wessel]

If I find out you're double dating in a relationship with, it's over immediately.

I dropped a woman that somewhat admitted to this a couple years ago before I met my current girlfriend. She was hanging out with another guy while I had been at work. She said that he was a "friend". I wondered if she told him that I was just a "friend" that she was hanging out with. I don't like playing stupid games so instead of fighting with her about it, I lied and told her that I couldn't make it for our date and said I had to go mow someone's lawn. The conversation was left at "maybe tomorrow" and we never talked to each other again. For two weeks she treated me like crap. I was sick of her attitude and it was a relief to walk away from her. I felt like I could finally breath again.