While Rey is off training with Luke on Ahch-To, Finn and Poe start a relationship. Poe "knows" Finn only wants to be him because Rey isn't there and when she comes back their relationship will end, but he's just happy to have Finn in his life in any way he can have him. He'll be totally fine when Finn inevitably breaks things off to be with Rey!

Except Poe's kind of a bonehead and that's not what's happening at all, but try to convince him of that.

I just want Poe convinced he's going to get dumped while wishing he could just be brave enough to step aside so Finn and Rey be happy together, and Finn and Rey convincing him they both want to be with him.