I've had the same few fellas messaging me on Facebook on and off for two years, the duration of my current relationship, and this is how we have started handling them. We do it as a team. There's none of him taking my phone and going through it, but I definitely let him know when somebody steps out of line and gets too friendly with me, just so he doesn't think I'm hiding anything (which he wouldn't so I don't know why I still show him, but if a girl did this to him, I know that I would want to know.)

So here are the pictures of how we handle that situation.

This is obviously from a few months back, but same fella as the picture below

Idk why I'm posting this but the other post just kinda pissed me off and I wanted to show how it works when there's trust in a relationship without one or the other being controlling about it.

Enjoy.

Update: I've tried not responding and blocking but he just makes new accounts, he doesn't get the hint.