Should I let this go and just ignore it or should I say something and what should I say?

Me and my girlfriend have been exclusive for 6 months and its been perfect, but for the past 4 days its been weird... she use to be with this guy that she was going to get married to and right before they was going to move in together he broke up with her and crushed her, It took her a long time to get over him and I stayed with her through all of it and she finily got over it, well about 4 days ago he texted her to come to one of his shows he is a proformer plays music and they have been texting sence she said that she would take care of it but she keeps texting hime.