Eh, he was? Didn't they do it only once, though, maybe twice... and back when he had not even begun yet being lovey dovey with "S roid" Iro?
Anyway, that relationship with Tess was so toxic, so very toxic (just from the dialogues alone, and even before we learned about Jin) that felt more like they were 2 people self-cutting instead of having sex... Nothing pleasant about it to get jealous over (I mean, it looked so toxic and self-harming it felt like Iro should be worried more than getting angry...)
Well I haven't read it all recently but the last time he slept with Tess was like 7 chapters ago. Then it came to such an abrupt ending it was pretty fresh in my mind still. But I totally agree it was toxic
the one thing that put me off this story was the fact that Rene was constantly sleeping with the other guy. i don't really get what was up with that Jin guy but Rene still seems hung up on him and Tess. And frankly insincere in his feelings