<human>: I'll be blunt I'm getting kind of sick of this. I've only recently as in maybe the last two years started dating, but with every girl I've even been interested in, or started dating I have an acquaintance/third party/other male try to hook up with them. Either while I'm flirting with them, dating them, or etc. I didn't let this bother me for a while since none of them cheated or anything. 

A large part of my problem with this is he constantly says he is dating a specific girl (who in my personal opinion looks like the most disease riddled person I've ever met), while he keeps going after girls I'm interested in. Hell one girl was crying when she found out someone in her family had cancer and I was holding her, and he asked her out in the middle of this. It's like really? The worst part about all of this, is HIS girlfriend is aware of all of this. 

Now I'm a fairly confident person and all, but I know after I had asked my now girlfriend out, he asked her out like a week later which she rejected. However today, I found out he has been stalking her facebook for like the past week and begging her best friend to give her, her phone number.

I'm getting tired of having to worry about this guy intruding into my life, try to "steal" any girl I'm interested in, "convincing them to cheat", etc. I know I have a tendency to be paranoid about things but this to me is just becoming out of hand. 

And no, I'm not making a throw-a-way because I know he uses reddit and if he sees this maybe he'll reconsider his actions and how frustrating they are making me.

Can you succinctly summarize the text in 1-3 sentences?
<bot>: Male third party is attempting to get with any girl I'm seeing/dating/interested in even though he has a "girlfriend" and yes, his girlfriend is aware of all of this.