<human>: Can you provide a brief overview of the text?

If so, what happened? 

Why I'm asking - I've recently had to go NC with a male friend (37M) who was pursuing me before getting married, and I kept turning him down. He continued his behavior after I got married, and kept begging me to leave my husband to be with him.

He was driving me insane. After talking with a few close friends about the situation, they suggested that he might be intentionally trying to break up my marriage as a sort of revenge somehow for rejecting him (I first rejected him several years ago - I was with the same guy, my now husband, and he was living with his girlfriend She recently kicked him out). This seemed really twisted and far fetched, but the more that I think about it, maybe it isn't. Their theory is that it's his goal to get me to leave my husband, and then dump me so I feel as shitty as he does.

Something similar happened to me when I was younger. I dated a guy for a few weeks in high school, and then broke up with him. 10 years later, he wanted to try again. After a few weeks, he dumped me...in a voicemail. After we'd slept together. 

So, I'm curious to poll the r/relationships community about this - if it's happened to you, or if you've done it, and why.
<bot>: Former friend who begged me to leave my husband multiple times has me wondering how common it is for bitter rejected people to try to ruin relationships. Has it happened to you?