He must have really like him then. A lot of people stay in the relationship like that, so many women wanted to get marry but the guy never bother to propose since they don't want actual legal commitment.
Its probably bc they both really do like eo.. Leo kept going the way he did bc he thought they were going steady since JJ never said anything.. JJ probably initially put up with it bc he was love blind, then probably thought Leo will change as the relationship progresses and eventually couldn't take it anymore for he kept bottling up stuff everytime Leo let him down from his pov.. Yes, Leo is kind of too dependent on JJ but many relationships like that work too bc you can only lean on your partner as much as they let you.. JJ doesn't communicate his boundaries and if he really can't tolerate Leo he should have broken up long ago instead of leading him on all these years..
A5 YEARS WITHOUT FUCKING GOOD COMMUNICATION???????HOW DID THAT FUCKING LAST THAT LONG???