N's compulsive digital addiction is contagious

I confessed on this forum how my number one issue has been Facebook stalking of my ex which allows me to know how often he and his ex (now his latest source) are messaging - basically hourly. I think that knowing that he's on the site so frequently disturbed me at first but now just keeps me mesmerized. Almost as if he passed his addiction onto me. I'm now maintaining a perverted digital connection to him. I know I have to stop this. I've been delaying unfriending him but I'm very close to finally doing it. It's just driving me insane, and that's on top of the insanity of having to see him often.

I have a chance to observe him at work for long periods of time, and I realized that it's not just the hourly Facebook messages with his ex. It's also one or more texting threads. Basically he looks like a drug addict who s constantly checking his phone to get a hit from Facebook, or a text, or whatever may come out of it. That happens every 15 minutes on average. It's scary. He can't even focus on what's going on around him.

Lately I also noticed that when I'm around him in public talking to our common friends, once the attention shifts from him to me and I start talking, he reaches compulsively for the phone and checks it. And then starts typing. It's incredibly rude and weird. It's almost as if he had a very strong urge to get a hit off his digital narcissistic supply sources at the very moment that he's forced to pay attention to me.

I don't know whether I need to interpret that as: 1. I'm the source of narcissistic injury as I stopped engaging and I've been ignoring him so he's looking for solace. or 2. he finds me so boring he needs to get a hit from higher grade supply.

This behavior actually makes it even harder to be around him at work. It hurts to see him do that. I wonder if he knows and he's doing it on purpose.