Hey if you are going to eat dinner with your ex at least inform your current boyfriend abo...

Also, the ex didn't sound like he knew about the current lover either.

Honestly, judging from how the younger dude was happy to keep hurting the older dude:
“I’m happy you got jealous.”
“Does it hurt?” - “Yes.” - “I’m glad it does.”

I wouldn’t put it past him to actually encourage this ex’s behaviour to get that kind of reaction from the older dude.

But I’m probably just looking too much into it. I just felt that pushing the dude’s insecurities was kind of unnecessary in those last two chapters.