If they'd left Ronnie all alone, he'd have bitched about that, too. No one is paying attention to him or his problem, boo, hoo.
He's the butt of everyone's jokes? He has roasted Mike on everything in the past - the Incarceration? Then he wants to drag Jenni's divorce into the mix? She's not broadcast every personal detail of her business on social media. He puts all of his shit on social media, so yeah EVERYONE is going to talk about it.
He's now tied to Jen forever. She's the mother of his child, so even after Arianna reaches 18 or 21, they're still going to be at events for her. He picked a crazy one, probably as they were both drunk or high when they got together, so he had a party buddy and fuck buddy all in one. He confused that with love, jumped into everything too quickly, so now he's stuck.
That he couldn't respond if he was coming to the wedding, rehearsals, etc., - what a douchebag. Pauly and Vinnie were trying to do that dance (it looked stupid, but hey they tried, doing whatever to make their friend happy). Then Ronnie was like oh because I missed a dance rehearsal, they're mad? It's because you are a HUGE douchebag. Mike should have cut him as a part of the wedding party when he didn't respond, but Mike is a bigger person, wanting to stay positive.
Sammi, you dodged a HUGE bullet, girl.
I don't see good things in Ronnie's future. He will eventually alienate everyone from this show, possibly his 'real life' friends and family, too. He's got major issues, some probably drug fueled, but other issues. He needs to get psych help stat. Maybe then he could see how to deal with the unstable Jen, and how to best be a good parent for Arianna.