AITA for canceling my proposal after my girlfriend and her ex tried to humiliate me?

My girlfriend raised her glass and said, "Honestly, Frank is the guy you date after the exciting men are done breaking your heart." Her ex was sitting 3 seats away. Our friends laughed. I touched the ring box in my jacket and said, "Then I'll stop taking up his seat." 10 minutes later, her best friend showed me the texts proving that the whole dinner had been planned. ---------------🐋Whale Tales🐋--------------- #reddit #stories #redditstories