Why is my used to be best friend spreading rumours about me?

Here is the sad thing..you are probably in middle or high school right? Well, Im a 21, and married and have the exact same problem! haha! I too had an arguement with her last summer, and her and her husband are saying horrible things about me to this day! They are also saying things to my only friend as well. For some reason though my friend wants to forgive her and be friends again....she's an idiot! haha! Anyway, I honestly think that when someone is still talking about you after this long of a time that there is something still bothering them, and it's probably jealousy. Otherwise, if you just stopped being friends and it was over, why couldn't she just drop it?? In my situation, this girl and her boyfriend always complain about me and my husbands relationship. Okay, I've been with him 6 years, and married for about 3. This guy and this girl on the other hand have been married, then got divorced, then re-married, then divorced, and are not getting married to each other again. Plus, I hear that this girl is still talking to her ex husband. Now, she is pregnant without insurance, and when she is having relationship problems. See what I mean? Why would they complain about my relationship when they are the ones in trouble? Jealousy!

I meant to say that they are NOW getting married again...lol